Springers: Barrel length, how does it effect accuracy?

[hawk45]

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)?

[rsterne]

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

[ray1377]

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

[Meann-Machine]

It doesn't.

[Papa Smurf]

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

[lefteyeshot]

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".

[pneuby]

Seems that would be the ultimate in crown protection, LOL.

[mbouchpcp]

When it comes to springers, how does barrel length factor into accuracy? 

Go here and you see what testing by the Cardew's revealed. 

Not saying it has not been done, but I don't know of anyone else who has done similiar research since them. 

[gloob]

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.

[jcwit]

   

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.

[gloob]

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.

[jcwit]

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.

[anuthabubba]

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.

[gloob]

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.

[jcwit]

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.

[gloob]

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?

[jcwit]

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

[gloob]

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.

[mobilehomer]

My Venom Dusk barrel is 18", my NP2 is 15 3/4". Guess which is more accurate and consistent? Just one example.

[gloob]

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.