Benjamin Prowler Barrel

[30harry]

I had another thread on here where I ask about accuracy and difficulty of shooting a springer/piston air gun but now I'd like to ask about barrel/pellet dimensions. 

My "new" .22 prowler (I took the first one back and got a brand new one) doesn't shoot any better/worse than the first one so I started to "investigate" the problem.  Groups of around 3" or so at 18 yards.
 Granted, I know nothing about shooting a springer/piston air gun but I can't seriously be that bad with it? 

One of the things I'm looking at now is how a pellet fits in the barrel.  My questions are:   

1. If you press a pellet into the barrel lands, how tight should it fit?  And how hard should it be to press the pellet through the barrel and out the muzzle?

2.  Should there be any "sticky" places in the travel through the barrel? 

3.  Does the head of the pellet actually "engrave" into the lands as it goes down the barrel or is it only the skirt that digs into the lands? 


I am using Crosman Premier 14.3 Hollow Points and Ruger 1.1g Superpoints and both exhibit the same characteristics.  The pellet is a little (not very much at all)  hard to press into the lands at the chamber end and then there is almost no resistance as you push the pellet down the barrel until it reaches the end of the barrel.  I believe (and I need someone more knowledgeable to verify) the initial resistance to pushing the pellet into the lands at the chamber end comes only from the skirt.  I don't believe the "head" of the pellet is even touching the lands.  And I think the same applies to pushing the pellet down the barrel with the low resistance throughout to be a result of the head not, or barely, touching the lands. 

I have put untold rounds down range shooting handgun metallic silhouette over the last 40 years and the vast majority of those were jacketed bullets and I am quite familiar with how the lands are pressed into the bullet which then generates the spin on the bullet and I don't see how this prowler could ever get the pellet "spinning" with just the skirt interfacing with the lands.  I would expect that the pellet "head" would be engraved by the lands as it moves down the barrel and the skirt would provide a lot of the "seal".  I also would not expect this to be a very low resistance process.  I would expect it to be a fairly difficult process to actually push a pellet down a barrel with just a cleaning rod.  It is so loose on this prowler that I almost expect the pellet to fall out the muzzle after the initial push from the chamber end. 

Now, as I push the pellet through the barrel and it reaches the muzzle end, it stops on something.  At this point, the head of the pellet is almost sticking out the barrel.  I'm taking this to mean there is something wrong with the barrel crown.  I can't see anything "obvious" but this is the only reason I can think of where the pellet would hang up right at the muzzle.  My plan is to re-crown the barrel but I won't be able to get this done for at least a week.

I have some "oversized" pellets coming in the next few days and I'll try them when they get here, but I don't think all my problems will be gone until the barrel crown situation is resolved.  And the sad part?  This is an air gun I spent $63 for at my local big box store.    They had an online sale for $68 and I got $5 off for using their app. 

Any thoughts/suggestions as to how to troubleshoot this problem or "setting me straight on how air guns really work" would be greatly appreciated. 

Harry

[Roadworthy]

Hi, Harry, and welcome to the GTA!!  You've figured out that the skirt seals the air column and the lands bite into it.  You may not be considering that when the air hits the skirt it is pushed more tightly against the lands.  The head of the pellet is slightly smaller but you can buy pellets with different head diameters to help compensate for different bore diameters.  The better the fit the more stable the pellet.

You can use a Q tip to get an idea of your crown condition.  Running a Q tip across the muzzle will help indicate any protrusions which may snag fibers.

As with firearms, the barrel should be cleaned before use.  This will have a significant impact on accuracy.  You should also note that unlike a firearm, the recoil of a spring piston airgun has an effect before the pellet even starts to move.  That is why it is imperative the gun be held consistently from shot to shot.  I use bore paste and bore polish to help ensure the barrels of my airguns are smooth.  I have no "sticky spots" once the pellet starts moving.

Many of the European airguns do have a choke or slightly reduced diameter for the last half inch or so at the muzzle.  This helps stabilize the pellet on exit.  I do not believe Crosman chokes any of their springer barrels.

[30harry]

Thanks again Tom,

I made sure to clean the barrel on this one before shooting so I don't think that is part of the problem.  I didn't know about the qtip idea but just tried it and didn't see anything.  I did run a Jewelers screwdriver lightly from inside the barrel to the outside at the muzzle and there are a couple of points around the muzzle where I could feel an irregulaity where the the screwdriver tip would not just transition smoothly from inside to outside. So I'm hoping re-crowning the barrel will fix that problem. 

Can you tell me if, on your airguns whether you are able to easily insert the head of a pellet into the muzzle end of your barrels? 

Also, I shot a few pellets into soft cloth rolled up and then examined them using a magnifying glass. On both the crosman and Ruger pellets the skirts were engraved by the rifling very clearly while the head of the pellet was not.  On approximately 30% of the circumference of the head I could just faintly make out impressions of the lands but could see nothing on the rest of the pellet.  I think the pellets need to be larger "oversized" but as I've said before, I know nothing about how pellets work in an air gun.  Maybe the skirt is the only important part??   Like you, I don't believe crosman would go to the expense of putting a tapered barrel on a $100 air gun. 

My oversized pellets are supposed to be here in the next day or so and I'll see how they work. 

Thanks again

[Roadworthy]

The heads of all my pellets insert fairly easily into the breeches of all my guns.  CPUM (Crosman Premier Ultra Magnums) seem to be the tightest fit.  They are also a heavy pellet and do not shoot well in any of my guns.

I select pellets by the end result - how they shoot - not by how tightly they fit.

Some of the cheapest pellets seem to give the loosest fit and the poorest accuracy results.

[30harry]

I just purchased a "pellet seating pen" and come to find out there is one more item I need to add to the equation of "how to make a prowler shoot small groups".  I never even gave any thought to pellet seating depth before and evidently this can be an important aspect of accuracy with some barrels/brands. 

I read where some guns like the pellet seated farther into the lands than others.  My job just became bigger.   

Still waiting for the oversized pellets and then the hard part begins. 

I don't necessarily want my pellets to fit tight in the bore.  It's more a matter of "what is the best way for pellets to fit".  As Col. Klink always said (or was that Sgt. Schultz?) , "I know nothing". 

It sounds like there is no "standard" and it varies with each gun/barrel/pellet.  Testing of the oversized pellets could be a real eye opener for me.  How does a 5.55mm pellet group versus a 5.50mm pellet and all the in betweens?   

[mentolio]

If you’re new to spring powered airguns and you’re getting sub 3” groups consistently, you may need more practice with your hold. Please don’t take this as me “cracking wise,” it’s just a fact that spring piston guns are harder to shoot accurately than just about anything. These guns recoil to the rear (like a firearm) when the trigger is squeezed, and then they recoil forward, all this before the pellet leaves the barrel (nothing like a firearm).

That said, if you are pushing pellets through the bore with a cleaning rod, there should only be very light resistance once the pellet is pushed past the breech. As long as the pellet isn’t “free-falling” through the barrel, it is less likely to be the problem. If you have “free-fall”, you’ve likely got some tight spots in an otherwise normal barrel vs. an “oversized barrel.” In this instance I have had some success polishing the tight spots out with J&B bore paste (as mentioned by Roadworthy), and in severe cases using fine valve lapping compound (beware...don’t get too aggressive!). After pushing the pellet through the bore, Check the head (in good light with a magnifying glass) for rifling marks. They don’t have to be deep, just uniform and all the way around. If your rifling is absent or inconsistent, try larger pellet head sizes. I have found that H&N Field Target Trophy pellets in the 5.53 head size usually work pretty well. As far as Redrow int: that’ll only help! While Crosman crowns aren’t always terrible, they are rarely great, and accuracy usually improves. Best of luck!

[dan_house]

back to basics....

check the stock screws at the pivot points., and the screw at the trigger. also make srue there is no side to side play in the lock up of the barrel......

[30harry]

Pyramyd air held up my oversized pellet order for some reason but now it's supposed to be here next week sometime. 

OK, I can hear the howls now. I did a rudimentary barrel crowning job on the barrel (I'm waiting on the tools to do a proper crown on it) .  I won't describe the process because it sounds ugly (it is ugly) . Anyway, I got rid of the problem with the factory crown. Now pellets push all the way out the muzzle very smoothly.  But, it still didn't shoot the crosman pellets any better.  Big groups and I'm thinking, "can Springer's possibly be this hard to shoot?".  No way ! I tell myself. 

While waiting for the pyramyd air order, I got in an H&N combo test pack of different H&N pellets.  I tried the green pellets (still 5.5mm pellets) and I was surprised by how tightly they fit in the chamber. Much tighter than the crosmans or the rugers.  Same size pellets, 5.5 but not the same size?    I was also surprised by the group size of the first 3 shots.  Like almost just one hole size at 18 yds!  So I answered my own question. Springer's are slightly more difficult to shoot than other guns.  Because of the low velocity, you have a lot more time to screw the shot up while the pellet is in the barrel. Plus, on the cheaper Springer's, the triggers are so bad as to be almost unusable. I already have the grt-III on order.  Also I replaced the CP scope with a bugbuster. World's better. 

I continued on with that 3 shot group and ended up with a ten shot group of horizontal .47 x vertical .66 and one of the vertical outliers was me. 

When the oversized pellets arrive, I have a lot more work but things are definitely looking up. 

More as this journey progresses. 

[silent_airman]

If you’re new to spring powered airguns and you’re getting sub 3” groups consistently, you may need more practice with your hold. Please don’t take this as me “cracking wise,” it’s just a fact that spring piston guns are harder to shoot accurately than just about anything. These guns recoil to the rear (like a firearm) when the trigger is squeezed, and then they recoil forward, all this before the pellet leaves the barrel (nothing like a firearm).

That said, if you are pushing pellets through the bore with a cleaning rod, there should only be very light resistance once the pellet is pushed past the breech. As long as the pellet isn’t “free-falling” through the barrel, it is less likely to be the problem. If you have “free-fall”, you’ve likely got some tight spots in an otherwise normal barrel vs. an “oversized barrel.” In this instance I have had some success polishing the tight spots out with J&B bore paste (as mentioned by Roadworthy), and in severe cases using fine valve lapping compound (beware...don’t get too aggressive!). After pushing the pellet through the bore, Check the head (in good light with a magnifying glass) for rifling marks. They don’t have to be deep, just uniform and all the way around. If your rifling is absent or inconsistent, try larger pellet head sizes. I have found that H&N Field Target Trophy pellets in the 5.53 head size usually work pretty well. As far as Redrow int: that’ll only help! While Crosman crowns aren’t always terrible, they are rarely great, and accuracy usually improves. Best of luck!

Yep, they are harder to shoot, but the flip side of that is you are more focused on the gun, more 'at one' with it. It's sort of a Zen thing I suppose. I am fairly new to springers and this year I am going to focus more on the basics and not worrying about dime sized groups. That will come in time. I am following this thread. There's a lot to learn here.

[30harry]

OK, received my oversized pellets and will be doing more testing tomorrow. 

I forgot to post after I tried the H&N pellets.  I bought the "combo" pack of H&N pellets which has about 40 pellets of each of five types that H&N makes.  They come in little glass vials.  Just for the heck of it and while I was waiting for my oversized pellets to arrive, I shot a few of the baracuda greens.  Don't ask me why I tried these first of the five.  Anyway, first three shots were an unbelievably small cluster of holes.  Like maybe a 1 and 1/2 pellet size hole.  I'm thinking "what the heck is this"?  So I continued to shoot them until I got to ten shots.  Eight of those went in a group of about .46 inches.  It seems like my saga has ended. 

Meantime, I decided to involve Crosman tech support in this saga. 

Me: Why won't my BP shoot better than 3+ inch groups at 18 yards.
TS: You didn't clean it did you?  If so, it will never shoot well until you shoot enough pellets through it to build up the lead in the barrel until it is much tighter.  You never clean a pellet gun.   

Me: Why do a lot of people say you have to shoot 500 pellets through an airgun before it will shoot well?
TS:  Because it takes that many pellets through it to build up the lead in the barrel until the pellets become tight and accurate. 

Me:  If that is the case, why does my BP shoot the H&N Baracuda Green pellets into about 1/2" at 18 yards while the Crosman doesn't.  There is no lead in the H&N green pellet, so it can't "build up" lead. 
TS:  I don't know. 

Me:  Do you know of any reason why the H&N green pellets shoot so much better in my BP?
TS:  No

Me: Why does it feel like there is a tight spot or catch right at the very tip of the muzzle (where the crown is) ?  I thought the pellet should transition smoothly from inside to outside.
TS:  Some barrels we make tighter at the very end of the muzzle to make them shoot more accurately. 

And so on.  Needless to say, I really felt down after that session. 

And I'm not quitting here.  No sir.  Mainly because the baracuda greens cost more than TWICE what I currently pay for target ammo for my .22 lr bullseye target pistol.  MAN those things are expensive!  KACHING !  Every time I fire a round downrange, there goes 11 pennies.  And here we are talking about an airgun I paid $63 for and it's a single shot springer to boot.  I have to find a pellet that shoots that well and doesn't cost an arm and a leg.  Otherwise, it's time to buy an MROD. 

[30harry]

What bothers me most about this effort is wondering why crosman pellets won't shoot in a crosman airgun.  They say to shoot enough pellets until the lead builds up in the barrel and the barrel then becomes tight enough that crosman pellets will shoot "smaller" groups.  Shouldn't a crosman airgun shoot crosman pellets to an acceptable level of accuracy right out of the factory?  Couldn't they just make the crosman barrel fit the crosman pellets?  Or maybe just make the crosman pellets fit the crosman barrel?   

Previously, I found that H&N baracuda green pellets shot like night and day versus the crosman pellets.  In this testing of oversized pellets, I found out they may have shot well but they did not shoot excellent.  With the oversized pellets in hand, I went to do more testing.  The only modifications to the stock prowler was the rudimentary crown job I did to it because of the messed up lands at the muzzle end.  I used the stock trigger with no mods and it was a bad trigger as all of them are stock. 

I shot all these pellets at the same time without cleaning or anything.  I shot five shot groups, one after the other.  I used the sportlock nestrest hard rubber rest on the front with the BP fore end resting in the sportlock and an extremely old rabbit ear bag on the rear.   This was sitting on an old wobbly table in my basement so it isn't what I'd call the best way to test but I was in a hurry.  All groups at 18 yards.  I shot all the groups just the way I would shoot any rifle with no special process or procedure.  The fore end resting on the "sort of hard" rubber rest.  And, I am NOT a bench rest shooter.  The vast majority of the shooting I have done over the last forty plus years has been with hard recoiling handguns in the handgun metallic silhouette sport. 

Baracuda green 5.50 - over quarter size groups
baracuda match 21.14 5.51  -  about quarter size
baracuda match 21.14 5.52 - maybe slightly over or about dime size
field target trophy 14.66 5.53 - under dime sized  (see pic)
field target trophy 14.66 5.54  - under dime sized but not as good as 5.53
field target trophy 14.66  5.55  - under dime sized with one flier taking it to about dime sized
JSB Match Diablo Exact Jumbo heavy 18.13  5.52  - under dime size but still not as good as the 5.53

Now it is entirely possible that some of the "fliers" in any of these groups could be my shooting skills or my setup not being sturdy enough.  I need to do more testing.  It is possible the JSB, HN 5.53 and HN 5.54 may all shoot equally well.  I just need to shoot groups with more shots in them and longer distances to see.  It may take me a while to get that much testing in. 

I just wish I had the oversized pellets prior to doing the crown job on the barrel just to be able to see the difference. 

The surprise to me is that anyone would buy a prowler and finding out how bad they shoot, would keep it rather than try something else.  I know I was about ready to give up before trying the oversized pellets.  Now I have a bunch of pellets I will probably never use. 

[mentolio]

Those are good groups for a (spring powered airgun) beginner. Assuming trigger is still stock (and terrible), I'd call those groups great. You will likely find your groups shrinking significantly once you improve the trigger (CDT, bearing mod, whatever you decide). This said, in my experience most springers do not respond well to a rest that is firm in front. You may get better results placing your hand on the rubber rest, then the rifle in your palm. Many of these guns, especially the "lower end" ones are extremely hold sensitive, and so require experimenting with technique to get it right. And one style of hold likely won't work from rifle to rifle. Then there's pellets...sheesh! Variety in manufacturers, weight, shape, length, etc. And believe this: a pellet your gun doesn't like this year could be next year's tight grouping slug. Best of luck and good shooting!

[30harry]

Those are good groups for a (spring powered airgun) beginner. Assuming trigger is still stock (and terrible), I'd call those groups great. You will likely find your groups shrinking significantly once you improve the trigger (CDT, bearing mod, whatever you decide). This said, in my experience most springers do not respond well to a rest that is firm in front. You may get better results placing your hand on the rubber rest, then the rifle in your palm. Many of these guns, especially the "lower end" ones are extremely hold sensitive, and so require experimenting with technique to get it right. And one style of hold likely won't work from rifle to rifle. Then there's pellets...sheesh! Variety in manufacturers, weight, shape, length, etc. And believe this: a pellet your gun doesn't like this year could be next year's tight grouping slug. Best of luck and good shooting!

Thanks,  One of the things I'd really like to know is "How are pellets supposed to travel down an airgun barrel"?  Meaning, for maximum accuracy, are the pellet heads supposed to be engraved into the lands or are they supposed to be what I would call a "bore rider" like they use in 50 BMG 1,000 yard group shooting?  Is the pellet head supposed to just barely fit in the rifling and the skirt is supposed to provide all of the "twist" surface or is it somewhere in between?  When I use "oversized" pellets, the only thing that is really oversized is the pellet head.  The skirt is already "oversized" to provide the seal for the pellet.  So it seems to me the pellet head should be a snug fit to the rifling to provide the maximum stability to the pellet as it travels down the barrel. 

It should be apparent, there is a ton more that I don't know about airguns then the very small part I "might" know about them.  This is a slow learning process for me. 

I will probably learn a lot more by moving the distance out to 40 yards or so. 

thanks again for the response.