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All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: hawk45 on March 31, 2015, 11:21:51 AM
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When it comes to springers, how does barrel length factor into accuracy?
Since the pellet is still in the barrel while the recoil is going on, is it better to have the shortest barrel possible to to reduce the effect recoil will have on the pellet, or does it not matter?
Is there a optimal length for different rifle powers (standard, mid, magnum)?
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If you are using the iron sights, a longer barrel increases the sighting radius, and hence your ability to point the gun more accurately.... Higher powered springers can benefit from a longer barrel in terms of the power delivered.... but the optimum length is still shorter than with most pneumatics.... Optimum barrel lengths for springers are in the 10-16" length, depending on power, but generally at the minimum length they get hard to cock.... Your comment about shorter barrels being less susceptible to movement during recoil has merit, and the lighter the gun for a given FPE, the more likely that effect....
Bob
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Hate to bring up an old post, but this begs the question.
Does the shorter barrel on the springer have anything to do with the springers power output originally?
Isn't it known that sub 12fpe guns are more forgiving in the shot cycle?
So saying that, wouldn't shortening the barrel on a "more" powerful gun help it more than shortening a lower powered gun?
Funny thing is, I've read that one of the best springers in the world, aka the TX200 has a barrel length less
than 12 inches.
And if you did cut a barrel down to 10 or 12 inches, would it not be harder on the piston because the pellet wouldn't be "in" the barrel long enough to help give it some resistance so the piston doesn't just slam forward like a dryfire?
I'd really like to know more about this, cause I'd love to shorten the barrel on my Crosman Storm.
One reason I'm hesitant is I can't seem to find out if its choked from the factory and if it is I don't want to mess
that up by cutting it off.
Thanks
Ray
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It doesn't.
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It may have been in 2002 when I got a Crosman RM 377 in .177 made for Crosman by Mendoza in Mexico . Mounted a 3x9 power scope and it was a tack driver . One ragged hole at 10 meters with almost any 7 or 7.4 grain pellet . It was back bored almost half way down the barrel . Sorry I ever gave it up , but I did keep the scope . --------------------------------Good Shooting to all -----------John ---- AKA -Papa Smurf
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Mendosa still does that. The Air Venturi Bronco and TF M8 that they make have only 9" of the barrel rifled and the TF M12 9.25".
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Seems that would be the ultimate in crown protection, LOL.
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When it comes to springers, how does barrel length factor into accuracy?
Go here and you see what testing by the Cardew's revealed. http://www.scribd.com/doc/124078012/CARDEW-The-Airgun-From-Trigger-To-Target# (http://www.scribd.com/doc/124078012/CARDEW-The-Airgun-From-Trigger-To-Target#)
Not saying it has not been done, but I don't know of anyone else who has done similiar research since them.
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I have some thoughts on this. It started with the purchase of a Ruger Explorer rifle that couldn't shoot quarter-sized groups at 9 yards. The particular behavior of this rifle got me thinking about the Cardew testing, and out came the hacksaw.
All testing was done at 9 yards, FTR.
The rifle is extremely light in weight, at 4.5 lbs, and the power is very low at about 500 fps in 177. When the gun is fired, the scope hairs "teleport" from POA to somewhere on the order of 15 MOA below POA faster than I can perceive. So when I fire the gun, the very next thing I see is the scope hairs bouncing around and moving laterally to varying degrees (generally to the right) at a level that is about 15MOA below the original POA.
The only pellet that gun would group with, at all, was one of my lightest and smallest (in head diameter) pellets. This pellet grouped larger than a quarter at 9 yard. The other pellets scattered more than 3" groups, or more than 30MOA, and POI moved to the right. The heaviest pellet (10.5) patterned about 20-30MOA to the right. I theorized that the pellet was leaving the bore AFTER the forward recoil of the rifle was stopped by my hands. This goes along exactly with what I am seeing in the scope when the gun fires. And the heavier pellets should be exiting the bore slightly later, making sense that they are being affected in the manner I was observing.
Things were complicated by the discovery that I was shooting with a couple of loose scope screws, likely the entire time. In my opinion, the gun became more accurate with each shortening of the barrel. At 7 3/4", the best pellet started shooting about 1/3" groups, with the best around 1/4". After some tightening the scope screws, the gun shoots sub 1/4" groups at 9 yards.
The gun also groups about the same with 2 other kinds of wadcutters, now, which would not shoot before. And the heavier pellets, including the 10.5's, now hit close to the same POA; they shoot much tighter patterns (hesitant to call them groups, yet), and most of the stringing is now vertical, rather than all over.
In my estimation, barrel length can definitely affect accuracy of a springer. Another interesting thing that my observations suggest is that decreasing the power of a rifle can make it less accurate under the right conditions. And increasing the power might make it more accurate. If the pellet is leaving the barrel after forward movement stops, the POI will be very random. Increasing the power would do two things to help this. For one, the pellet would leave the bore sooner. And second, the recoil would be increased, giving the pellet more time to exit the bore before the rifle's forward momentum is stopped and it takes that first randomizing bounce event. Albeit, this specific behavior is probably only possible in very light and weak rifles. Much heavier, faster guns couldn't possibly end their forward recoil before the pellet exits. But it (shortening a barrel, up to a point) should, theoretically, reduce the hold-sensitivity of the gun. This is likely the reason for the shortened barrels in some higher end springers. Of course, go too short, and velocity spread will be adversely affected.
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In my estimation, barrel length can definitely affect accuracy of a springer. Another interesting thing that my observations suggest is that decreasing the power of a rifle can make it less accurate under the right conditions. And increasing the power might make it more accurate. If the pellet is leaving the barrel after forward movement stops, the POI will be very random. Increasing the power would do two things to help this. For one, the pellet would leave the bore sooner. And second, the recoil would be increased, giving the pellet more time to exit the bore before the rifle's forward momentum is stopped and it takes that first randomizing bounce event. Albeit, this specific behavior is probably only possible in very light and weak rifles. Much heavier, faster guns couldn't possibly end their forward recoil before the pellet exits.
If this were entirely true those shooting in the Olympics in years past when they used springers obviously knew nothing about what they were doing.
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How so? Did they extend their barrels and lighten their guns? Also, remember that Olympic guns must use open sights, so sight radius is a factor.
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How so? Did they extend their barrels and lighten their guns? Also, remember that Olympic guns must use open sights, so sight radius is a factor.
Doubtful they used a counter bored barrel.
Barrel extensions to the best of my knowledge are only used by the Small Bore shooters, generally they are called "Bloop tubes".
I used to use one.
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Makes me cringe when I read about guys trying to base the merits of all spring guns on their limited experience with poorly engineered, built with even worse execution from inferior materials, bastardized 'semi-copies' of some of the best designed/manufactured, continually refined for decades, record winning/holding airgun designs.
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Makes me cringe when I read about guys trying to base the merits of all spring guns on their limited experience with poorly engineered, built with even worse execution from inferior materials, bastardized 'semi-copies' of some of the best designed/manufactured, continually refined for decades, record winning/holding airgun designs.
I for one, did not do that. I stated my belief that reducing the power of a gun can make it less accurate under specific circumstances; and furthermore, that this specific and dramatic example of behavior could not possibly occur on most air rifles. I believe in every case of a rifle that shoots halfway decent, the pellet is gone before the forward momentum of the rifle stops. Additionally, extrapolating the merits of all spring guns based on just the best ones might also be considered narrow-minded. And furthermore, I think a rifle that shoots decently (sub 1/4" at 9 yards is decent, in my opinion) can provide a valid data point, regardless of where it was made or how much is cost.
Interestingly, in my specific example, the Ruger Explorer is a rebranded XS-16 rifle with the spring from an XS-12 rifle, which reduces the power from 660 fps as it was originally designed, down to 495. Furthermore, the XS-12 rifle has the same barrel length as the XS-16, but the XS-12 weighs 30% more, giving the slower moving pellet more time to exit the barrel.
Furthermore, after setting the spring on this rifle by intentionally leaving it cocked for 5 hours made the groups open up, with the original barrel.
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Makes me cringe when I read about guys trying to base the merits of all spring guns on their limited experience with poorly engineered, built with even worse execution from inferior materials, bastardized 'semi-copies' of some of the best designed/manufactured, continually refined for decades, record winning/holding airgun designs.
I for one, did not do that. I stated my belief that reducing the power of a gun can make it less accurate under specific circumstances; and furthermore, that this specific and dramatic example of behavior could not possibly occur on most air rifles. Additionally, extrapolating the merits of all spring guns based on just the best ones might also be considered narrow-minded.
Interestingly, in my specific example, the Ruger Explorer is a rebranded XS-16 rifle with the spring from an XS-12 rifle, which reduces the power from 660 fps as it was originally designed, down to 495. Furthermore, the XS-12 rifle has the same barrel length as the XS-16, but the XS-12 weighs 30% more, giving the slower moving pellet more time to exit the barrel.
Furthermore, after setting the spring on this rifle by intentionally leaving it cocked for 5 hours made the groups open up, with the original barrel.
So this is what happened on this particular piece, now try it on 10 more pieces of the same make & model to prove your findings.
Then move on to another make & model and start all over again.
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That's a great idea. Maybe by posting this info on an airgun forum, in a thread specifically about barrel length and accuracy in springers, I have added one of these data points. Eventually, if it does not get derailed too badly, there may be further data points added along the way by other airgunners, if not by myself.
Another less interesting data point is my Venom. I chopped the barrel down from 18.5" to 12". Accuracy is essentially the same; it was great to start. But POI rose by about 8-9MOA. That could just be where the barrel was cut, but the change in POI follows what would be expected. The pellet necessarily leaves the bore sometime after the piston has stopped and the rifle has started to move forward and down. Getting the pellet to leave earlier would raise the POI and should theoretically make the gun at least a little less hold-sensitive.
I'm not sure what the fuss is, over my post. Are you arguing that barrel length does not affect accuracy? Why are some barrels longer than others? Why is the TX200 barrel only 9" long?
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Because to me in general the manufacturer knows what they are doing, that is why they have an R&D dept. But who knows, I may be entirely full of it.
I will say this, Please oh please stay away, far, far away from my collection of air guns and firearms. Get to close and you may well be in deep trouble! LOL
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Because to me in general the manufacturer knows what they are doing
This is likely the case, here, as well. Neither the manufacturer nor the design engineers of the XS-16 rifle are the ones that likely decided to put the XS-12 spring in this gun. It was more likely a distributor that made that decision.
I am 100% in agreement that in any rifle that shoots halfway decent, the pellet is long gone before the forward momentum of the rifle has stopped. My observations of the Ruger are not the norm.
But in any case, there is obviously a point where a springer rifle barrel is too long for any given pellet, and there is obviously a point where it is too short for the same. (And I believe my Ruger might be an example of the former). There are many reasons to make the barrel longer than necessary: to make the gun easier to cock, for esthetics, loudness/muzzle blast, balance, and for sight radius. As other people have stated before me, without being harassed, the ideal barrel length for an average springer might be well shorter than what is the norm, from a strictly accuracy-centric viewpoint.
There may very well also be some leeway in what is strictly ideal from an accuracy-only standpoint, based on the best balance between standard deviation of muzzle velocity, exposure time to recoil, recoil characteristics of the gun in question, and of what range of pellets one wishes to shoot best in said rifle. A few inches here or there might be half a dozen of one, 6 of the other. But even so, there is likely some compromise made in many rifles concerning barrel length, for consideration of factors other than accuracy.
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My Venom Dusk barrel is 18", my NP2 is 15 3/4". Guess which is more accurate and consistent? Just one example.
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I would guess the NP2, because it is more expensive, lol.
In my hands, it would take awhile to tell a meaningful difference, and I suspect that any difference due to barrel length of an already good-shooting rifle would come into play largely regarding consistency/flyers/hold-sensitivity. My Venom is close to as accurate as I am, already, but I will be taking note of long-term observations post barrel cut.
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Using the same springer rifle and the same pellet, that the gun likes, the pellet should leave the end of the barrel about the same moment every shot during the firing cycle. Using the artillery hold is suppose to let the gun do what it's going to do instead of fighting it, so the end of the barrel will be in the same place every time when the pellet exits the end of the barrel. So poi should be in the same place every time. Then adjust or zero sight or scope accordingly.
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the pellet should leave the end of the barrel about the same moment every shot during the firing cycle.
Yes, it should be quite close.
With my particular example of the Ruger Explorer, the artillery hold did not work. And based on my observations, I believe it is because no matter how lightly you held this gun, the slow moving pellet would not leave the bore until after the very light rifle stopped moving forward from the relatively light recoil. At least in my adult hands. Maybe in a smaller 6 yr old's grip, it would have had a chance at grouping. Some of the other reviews suggested that lead free pellets are the only thing that would group in theirs. The lighter pellet may be able to get out of the bore before the first bounce. I never tried, because a gun that only shoots expensive lead free alloy pellets at 5 fpe is useless to me, unless it's unusually accurate.
Most of the reviews of this gun that call it accurate AND list group sizes were reporting 2-3" groups at 25 yards as being accurate. I found one old post on a forum about an Explorer that shoots dimes at 20 yards, but he didn't specify what pellet. My modified Explorer can certainly shoot sub dimes at ranges of at least 20 yards, now. Nothing but slightly ragged holes at 9 yards.
The Ruger, if my conclusions are correct, is simply an example of what happens when a barrel is grossly too long. There might very well be a large area of barrel length that will work fine out of any given springer. As Rsterne said in the very fist response, the lighter the gun, the more of a concern you may have. But all else equal, I think that in general, having a barrel that is a little longer than necessary is a common thing. Cardew testing suggests that our barrels do not need to be so long. And even if the gun shoots fine, changing barrel length could affect both standard deviation of muzzle velocity and hold-sensitivity. In addition, I theorize that making a barrel shorter could in some cases potentially tighten up the group horizontally, while not improving or even increasing the vertical spread. This is because the pellet would be leaving the bore while the forward (and down) movement of the rifle is at a higher rate (and it does not leave the muzzle at EXACTLY the same time), but conversely the rifle would have had less time to deflect left/right due to variation in hold.
The reasons for longer barrels are many, as I have already listed. In addition, manufacturers report the all important velocity numbers and cocking force numbers to sell rifles. The longer the barrel, the better those numbers. You might need an 18" barrel to get max velocity from a 4.5 grain pellet. But that last 6 inches might do nothing for a 7.5gr pellet.
Also there's parts availability. A manufacturer already uses a certain barrel in some of their guns. They have the manufacturing setup, already. They have inventory. And they already have fixed sights that work best for that barrel length. That is a pretty good reason to use a certain barrel length, even if it is not optimal.
I don't know if tuning of springer barrel length will ever be mainstream. There are a lot of people that think longer barrels are inherently more accurate. There are a lot of people that thing the designers and manufacturers have carefully tailored the barrel length for accuracy, and the only things one can improve on a gun are the kind of lube, to put a little tar on the spring, and to do a little deburring. But barrel length is a factor that some people are willing to experiment with, and which may in some cases can make a much bigger difference than moly vs lithium grease.
I also wonder about springer pistols with the little detachable cocking aids. Why not just permanently add another 2-3 inches to the barrel? I think in some cases, it's because the gun would no longer hold a group. The Ruger Explorer is essentially a springer pistol with a 14" barrel, and I'm convinced it is an overall fail, out of the box.
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Just don't see it that way at all.
Regarding the manufacturer already being set up for a certain part and having a certain part already in inventory, this logic Ford should still be making Model "T"'s And the same for all manufacturing.
But in reality it doesn't work that way, my belief is that the manufacturer does in fact know what they are doing.
Now is you would do the same with 20/50 or 100 rifles of the same model and found the same facts out across the board I might consider your findings meaningful. But one rifle to me means little to nothing.
Thank Goodness you are not working to find a cure for whatever.
But keep on with your experiments, you seem to be getting a kick out of doing it. Have at it.
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I also wonder about springer pistols with the little detachable cocking aids. Why not just permanently add another 2-3 inches to the barrel? I think in some cases, it's because the gun would no longer hold a group. The Ruger Explorer is essentially a springer pistol with a 14" barrel, and I'm convinced it is an overall fail, out of the box.
Just Super Glue the assist to the barrel, if it has a hole in it of course, if not, drill a hole.
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AA pro sport is known as a tack driver. Copy and pasted from PA website.
The specs show that the Pro-Sport has a 9.5" Lothar Walther barrel. We've had a number of customers email us that this is a mistake. It is not. The barrel really is only 9.5" long. The gun has a shroud over the barrel, and the shroud is longer than the barrel. It gives the illusion that the barrel is longer than 9.5 inches. It isn't! The barrel is the rifled portion.
The Air Arms Pro-Sport has earned a faithful following among field target shooters because it's remarkably accurate and easy to shoot.
However, you don't have to shoot field target to appreciate this gun. In fact, you might want to get the .22 for hunting rats, mice, rabbits and squirrels. It's super-quiet because it has a barrel shroud that helps deaden the sound.
The Monte Carlo stock and raised cheekpiece are just a couple of the gun's ergonomic features. Air Arms has increased the amount of area that is checkered on the grip and forearm. If you've ever had sweaty palms while hunting or during a match, you'll appreciate the extra gripping power!
The Pro-Sport has a 12-groove Lothar Walther barrel and comes to you in a tuned state. That means you won't have to spend hours or days fiddling with the gun to make it shoot perfectly.
The weight given in the specifications section at left says 9.03 lbs., but that's for the walnut stock. The beech stock is only 8.60 lbs.
This rifle does not come with a scope or sights, so remember to pick up a scope when ordering!
Don't forget to pick up a variety of recommended pellets, which are listed in the AMMO link below. Select appropriate accessories, including targets and a scope, by clicking on the ACCESSORIES link.
youTube video
See manual
See schematics
other products by Air Arms
Unit Converter for Airgun Measurements
Item Description Caliber Max Velocity ItemCode Stock Grip Color
Beech stock
Limited Quantities
This item is not eligible for coupon discounts
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Could you guys tell us about the recrowning and choking (two well known operations considered mandatory to improve accuracy/grouping) you did after hack-sawing the barrel?
The longer barrel for increasing MV is needed only in expanding gas type guns such as co2, PCP, pumpers or powder burning types. A springer uses a comparatively small, short burst of air which is why they are generally much quieter at the muzzle.
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AFAIK, there's only one guy in this thread that is dumb enough to cut their barrels down with a hacksaw. That would be me.
1. Hacksaw
2. Beltsander to get out the hacksaw marks
3. File to get out the beltsander marks and to really square up the end (by eye).
4. Optionally, take an oil stone(s) and work down as fine as you want, to remove the marks from the file. I have course silicon carbide stones, medium AlOx, and I even finish with an Arkansas stone. All this is completely cosmetic.
5. Chamfer with a chamfering tool. I used an RCBS chamfer tool I use for reloading. I think it's high speed steel. But I understand any old countersink from the hardware store will work. Air gun barrel steel is usually very mild
To debur:
1. Take a brass rod or bolt, and stick it in a drill. Take it to the belt sander if needed to make the end roundish and just a little larger in diameter than the bore.
2. Break a chunk of green buffing bar with a knife, and put a couple drops of mineral oil on it. Melt it with a heat gun and mix it up a little.
3. Dip the end of the rod into the abrasive.
4. Stick the rod onto the end of the barrel and run the drill on a low speed, counterclockwise (to remove the burrs left from chamfering clockwise)
5. With the butt stock on the floor and keeping the drill still, move the end of the barrel around in a circle, so the brass rod moves around and hits all the spots.
Repeat 3-5 until the burs are gone. I check this, periodically, with a wooden stick, to see if it catches. And once it passes that test, I move on to sticking a pellet head-first into the crown and then withdrawing it to feel if it catches. This test is a lot more sensitive then using a cotton ball, for me.
Crowning a barrel isn't hard. And doing a better job than a bottom-dollar assembly line is downright easy. It requires no special equipment or skill. The only hard part is making the decision to do it.
With my Venom, I removed the plastic muzzle attachment, first. I just gripped it and twisted, but I may have got lucky. My Venom is 3-4 years old, and the adhesive might have been a little worn out, already. After crowning, I put it back on.
My barrels weren't choked. Pellets are still tight in the muzzle. If your gun has a choked barrel, you will almost surely be able to find out about it in the adverts or other specs for the gun. You can also easily check with by pushing pellets in from the chamber end. If your gun is choked, the pellets will be pretty easy to push into the breech. If you have a cleaning rod, you can push the pellet all the way to the muzzle to feel for a choke.
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You should be working as a rifle smith for one of the US Olympic Teams. Give us a head start!
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What's with all the hostility here?
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Who's hostile? I'm sure not, mayhap have a difference of opinion but not hostile at all.
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Thank Goodness you are not working to find a cure for whatever.
Sounds a bit hostile to me too.
Most of the comments in this thread are useful. As stated earlier, each air gun is different. And if the manufacturer always knew what is best, there would be no need for tuning or modifying, ever. Most of us here like to tinker. Rightly or wrongly. ;)
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Thank Goodness you are not working to find a cure for whatever.
Sounds a bit hostile to me too.
Most of the comments in this thread are useful. As stated earlier, each air gun is different. And if the manufacturer always knew what is best, there would be no need for tuning or modifying, ever. Most of us here like to tinker. Rightly or wrongly. ;)
You are entitled to your opinion. Have fun!
I just look at it a bit different, I guess.
I make note that the most accurate air guns out there do not have short barrels.
I also make note that cutting off and shortening a barrel on one gun and posting the findings as fact proves little to nothing. Do the same on a scale of a number of the same make and model then post the findings there may well be something to it.
Further making note how one manufacturer uses a short barrel and a sleeve does not make that a rule for all makers to use a short barrel and a sleeve to accomplish an accurate arm.
Using the logic that shortening the barrel accomplishes said accuracy would be similar to finding a pellet that gives accuracy in one air gun and assuming it gives excellent accuracy in all air guns.
Just doesn't work that way!
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And if the manufacturer always knew what is best, there would be no need for tuning or modifying, ever. Most of us here like to tinker. Rightly or wrongly. ;)
Granted there is always room for improvement.
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And if the manufacturer always knew what is best, there would be no need for tuning or modifying, ever. Most of us here like to tinker. Rightly or wrongly. ;)
Granted there is always room for improvement.
Happy shooting! :D
Personally, instead of cutting a barrel shorter, I would rather tinker with barrel weights, pellets, etc. There are reasons to cut a barrel down, to make it "handier", or if the crown is damaged. Or...to experiment.
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Nah man...search cut barrel long enough and you'll find dozens of hacksaw guys in here...
Easiest way to tell if a barrel is choked is to push a pellet or six through it from the breech end.....also a good way to tell if you tight spots loose spots or like my Titan a deformed muzzle....a round head brass wood screw and valve lapping compound is the combo i used to recrown the Titan...
Search recrowning.....search choking for ideas on how to accomplish that too....
And don't bother with people that talk about competition shooting and manufacturer knows best, those people only point airguns that somebody else tuned, what you are doing is tuning your gun to you, your hold your sight line your reaction to the recoil.....what you do might work for others and might not...what matters is if it works for you...
I did many things to the airgu in my pic before it shot well in my hands.....it was originally a Titan gp np and the people that have shot it since i worked it over agree it shoots well for them too....how it would have shot for them before my work is the real question for comparison, too bad we don't know...