Grind, cut , or sand off the crown on any barrel , make it level and that rifle will shoot just as accurate or better, the crown is only protection for the rifling, disagree ? Prove me wrong.
- The AGN App is ready! Search "Airgun Nation" in your App store. To compliment this new tech we've assigned the "Threads" Feed & "Dark" Mode. To revert back click HERE.
PROVE me wrong
- Thread starter Rawroots
- Start date
G
Guest
Guest
I'm not a gunsmith and I'm not an airgunsmith. So clearly I am not qualified to answer your challenge.
If it was cut dead square with the bore and polished to a nice smooth surface then I'd think you are probably right. There clearly would be problems if it were not square with the bore or had rough edges around the circumference.
Oh, you know there are "choked" airgun barrels. I think the reason for that is to get a good consistent spin on pellets which only lightly engage the rifling during acceleration. Spring rifles (even PCPs I would think) can't push projectiles which fit the bore tightly (as in the PB world where they engrave rifling on copper jackets). Most of the old timers swore by choked barrels.
Why do you make this challenge and what qualifications do you have to make the assertion?
Upvote 0
There is a reason people recrown a barrel after its cut down. Any method you cut the barrel with will leave a burr at the muzzle. Sanding, cutting, or grinding will also leave a burr which would probably affect accuracy. How the projectile leaves the muzzle is probably the most important part of accuracy.
Upvote 0
OK let’s pretend that it’s true and the crown only there to protect the rifling. So what would be the purpose of removing the crown or is there an argument for NOT wanting to protect the barrels rifling?
Upvote 0
I would say protecting the rifling is secondary. The primary goal of the crown is to establish the last point of contact the projectile has with the barrel just before it is released out into the world. Ideally it is absolutely burr-free and perfectly coaxial so the pellet's skirt loses contact around its full perimeter at precisely the same point in time. As such, a plain 90° can work splendidly...unless or until you ding it against something. That's not a concern for shrouded barrels or those wearing an LDC.
Sometimes a piss-poor looking crown will not adversely affect accuracy but it's something any competent gunsmith will strive to get right. Even shadetree gunsmiths will try to get it right...
Sometimes a piss-poor looking crown will not adversely affect accuracy but it's something any competent gunsmith will strive to get right. Even shadetree gunsmiths will try to get it right...
Upvote 0
Well said, the crown doesnt make the accuracy, it helps keep nicks and burrs from causing accuracy loss. Consider this....a really sharp knife will loose its extreme sharpness quickly unless extra care is used to protect that cutedge, where a slightly duller knife can take more abuse before loosing its cut edge. Why do you remove sharp edges and burrs from a piece of steel? That sharp edge is easily damaged just like a barrel end without a crown!
Upvote 0
I cut a 19 inch .177 barrel down to 6 inches. I made sure the crown was as close to 90° as possible and made sure the chamfer was clean. The gun is more accurate for me because the short barrel creates a shorter lock time. HTH.
Upvote 0
My belief is. A recessed crown is there to protect the rifling.
Hack saw barrel, file square to bore then hone/stone with a hard Arkansas stone.
But you should really know what your gun is capable of before you cut down your barrel. That way you will know if you actually made it better , worse or the same as before.
Hack saw barrel, file square to bore then hone/stone with a hard Arkansas stone.
But you should really know what your gun is capable of before you cut down your barrel. That way you will know if you actually made it better , worse or the same as before.
Upvote 0
There is a very good article on a powder shooting site talking about this. The guy took a 24" barrel and shot groups and took velocity numbers. Then he cut it down an 1" after every session, and kept going until he got down to like 12" or so. He did nothing to the crown and just left it rough after cutting off with a chop saw.
.308 Win Barrel Chop Test: How Velocity Changes with Length « Daily Bulletin (accurateshooter.com)
Now this is for a 308, but it goes through everything nicely
.308 Win Barrel Chop Test: How Velocity Changes with Length « Daily Bulletin (accurateshooter.com)
Now this is for a 308, but it goes through everything nicely
Upvote 0
I'd say the bore needs to be square, and devoid of imperfections in order to launch the projectile consistently.
I've done a few chop and recrowns successfully with a hack-saw, table sander (to square and dress the muzzle), and tapered stone and polishing bits to slightly counter-sink the bore/rifling. This is not an untypical result (a 1960's vintage Crosman Co2 rifle converted to HPA pistol)-
Three State Champion and three National Champion field-target titles.
Five consecutive five-shot groups at 50 yards averaged .66 and .67" center-to-center (on three different occasions to date).
I've done a few chop and recrowns successfully with a hack-saw, table sander (to square and dress the muzzle), and tapered stone and polishing bits to slightly counter-sink the bore/rifling. This is not an untypical result (a 1960's vintage Crosman Co2 rifle converted to HPA pistol)-
Three State Champion and three National Champion field-target titles.
Five consecutive five-shot groups at 50 yards averaged .66 and .67" center-to-center (on three different occasions to date).
Upvote 0
The problem is that the act of cutting is destructive and irregular. Doesn't matter if you cut perfectly square at perfect 90 degrees,. you are still cutting from ONE SIDE.
Therefore the lands and grooves on the side you cut FROM will have been deformed by the cut process in a totally different way from how the opposite sides lands and groves will be deformed. These abnormalities WILL effect the projectile as it exits the barrel. You can try to solve the problems created by these off side deformities, but unless you do it exactly the same all around, you will just add another degree of lopsidedness. The way to get all around the circumference nice and uniform? A crown.
Therefore the lands and grooves on the side you cut FROM will have been deformed by the cut process in a totally different way from how the opposite sides lands and groves will be deformed. These abnormalities WILL effect the projectile as it exits the barrel. You can try to solve the problems created by these off side deformities, but unless you do it exactly the same all around, you will just add another degree of lopsidedness. The way to get all around the circumference nice and uniform? A crown.
Upvote 0
NOT wrong in my case.
I hack sawed about 3" off of the end of a barrel, "filed" it square and flat, put a 45° chamfer on the end. All by hand (and a drill motor). Added an adapter for a silencer, than added a silencer.
The gun shoots as well as it did before my "hacking".. NO change in accuracy or the point of aim. I never removed the barrel from the action/gun. Though I did stuff one of those cotton "cleaner" pellets into the end of the barrel to keep chips/filings out of the action of the gun, before starting.
Mike
I hack sawed about 3" off of the end of a barrel, "filed" it square and flat, put a 45° chamfer on the end. All by hand (and a drill motor). Added an adapter for a silencer, than added a silencer.
The gun shoots as well as it did before my "hacking".. NO change in accuracy or the point of aim. I never removed the barrel from the action/gun. Though I did stuff one of those cotton "cleaner" pellets into the end of the barrel to keep chips/filings out of the action of the gun, before starting.
Mike
Upvote 0
To me if any portion of the barrel remains in contact with the projectile for even the smallest moment of time more than any other portion of the barrel it will cause drag on that one portion of the projectile and the projectile will be moved off the line of sight of the bore. I believe the effect is proportional to the amount of time the small portion of the barrel touches the projectile and the literal amount of degree the circumference of the crown is not perfectly perpendicular to the bore. An extreme exaggeration would be shooting along a plate of steel just past the crown almost parallel with the bore and leaning into the line of fire so the projectile would graze the steel plate and be deflected away from the line of bore sight. This is why I believe how perfectly perpendicular the crown is to the bore of barrel is so very important. This is my personal opinion based on articles I read in powder burner magazines over my many years of shooting from bb guns to target crowned .22 target rifles. Most target barrel crowns are done on a lathe. It doesn't mean they cannot be done by hand. And the true tests are the Palmer 1000yds matches. The shorter the range the less the negative effects are. Some people have the hand eye coordination, confidence and steadiness necessary. At 72 I leave crown polishing to others using a precision machine tool.
Upvote 0
So far I have turned two ridiculous shooting scatter guns into 1.5 inch shooters at 50 yards, these had boogered up factory rifling at end of barrel, both had a half inch cut off then used a slug with lapping compound to clean any burrs, super glued a hot dog stick to hollow skirt of slug as a handle. The avenger is one of the makes that doesn't have factory crown, most modern air rifle barrels are now protected by moderators. But I enjoy hearing everybody's opinion and input.
Upvote 0
I think it depends on how much you trust the barrel. A less expensive gun may not have the same level of machining as an FX barrel. Personally, I'd never chop up and FX barrel and expect to retain accuracy. However, an Avenger, Gauntlet, or other less expensive gun might be a different story. While FX has good quality control and massive amounts of research into their barrel designs, others, not so much. I think that's a judgement call
Upvote 0
The initial “prove me wrong” did not include the fact that you lapped off the burr after making the cut. I took it that you hacksawed, sanded, or ground off the end of a barrel and left it as is. I do have to ask would a proper crown improve your 3 moa group? Maybe a little burr still remains. Lapping is not an efficient way of removing material even small amounts like a burr. Your lead slug wears down rapidly and burrs are not always visible from the side they got pushed over from. Unless you use a bore scope from the breach or pin gage the bore there is no way to know if the burr is completely gone. Another way to check for a burr is to insert a small pick into the bore and drag it out very lightly at different points all the way around the bore being carefully not to apply too much force so you don’t scratch the bore. If there was a burr there you would feel it with the pick.
Upvote 0
the barrel opening 'has' to be square or the gas wont escape evenly at the pellet base when it leaves .. you arnt going to achieve that with grandpas hacksaw trust me and if its cut properly with a lathe or jig then your going to put chamfer on it to finish the edge period ..
Upvote 0