Rimfire Barrel Thought

[RTH1800]

I’m not a machinist or gunsmith.
I have long wondered about “fixing” less than stellar rimfire barrels.
There is a school of thought that a small amount of “choke” aids in accuracy. Why not utilize some type of hydraulic compression to the muzzle to build in a tenth or two of “choke”? (.0001 - .0003)This for a barrel that simply is not preforming as well as we would like but otherwise appears fine.
Would it take more pressure than could be readily applied?

 

[Hi-NV Shooter]

I’m not a machinist or gunsmith.
I have long wondered about “fixing” less than stellar rimfire barrels.
There is a school of thought that a small amount of “choke” aids in accuracy. Why not utilize some type of hydraulic compression to the muzzle to build in a tenth or two of “choke”? (.0001 - .0003)This for a barrel that simply is not preforming as well as we would like but otherwise appears fine.
Would it take more pressure than could be readily applied?

Choke would be incorrect description of what is sought for a RF barrel. taper is more of what is wanted. you want from the chamber end to have the bore gradually get tighter as you get near the muzzle end. you could re-lap a barrel to try and make it shoot better.
but in your question of trying to compress the bore you would not be able to control how round it would end up.

Lee

 

[68hoyt]

RTH
I have thought the same thing , machine a interference fit sleeve about 4” long for the muzzle end of the barrel , freeze the barrel a day heat the sleeve and tap it on , see if it helps
Depending on how thick the barrel is the sleeve would have to be thick enough to keep the barrel compressed , would be interesting to see if it worked on a known problem barrel

 

[Emerson0311]

RTH
I have thought the same thing , machine a interference fit sleeve about 4” long for the muzzle end of the barrel , freeze the barrel a day heat the sleeve and tap it on , see if it helps
Depending on how thick the barrel is the sleeve would have to be thick enough to keep the barrel compressed , would be interesting to see if it worked on a known problem barrel

Extra weight added to the end of the barrel might have a larger effect than the squeeze. Some barrels have the forward section profiled much thicker than the rest. I doubt the squeeze would make an identifiable difference. Lots of Rimfire ideas but no one seems to be able to show straightforwardly what helps.

 

[whatsupdoc]

And after all that the ammo is still the weak link.

 

[68hoyt]

Emerson
If the squeeze didn’t make a difference how come if you cut the od of the barrel down the last few inches it sometimes makes a difference ( I can’t say it always makes a difference )

 

[jbell]

The juice wouldn’t be worth the squeeze. Just put a new barrel on that has been made and installed properly.

 

[nikonNUT]

There was a thread about using a hose crimper (10000psi) and a collet to squeeze a barrel but I agree with @jbell . Not worth it.

 

[RTH1800]

Like the different thoughts.

Since the cost would be little or nothing cannot see how it “would not be worth it.”

Nor do I know how it is you would know this if you have not tried it.

Nor is a new barrel a guarantee of better accuracy. Many new barrels “are not worth it.”

 

[Zap_Rowsdower]

I'll take a few barrels to work and throw them in our rotary forge and see if I can get a little choke on them

 

[BR7.62]

ive had thoughts along these lines as well.
they make swaging tools for shotgun barrel.
basically 3 steel cylinders that act like wheels you tighten them up and roll it around the muzzle of the barrel to constrict it to a smaller choke size.
would take quite an increase in size and strength to transfer the idea to a heavy barrel...

i like the idea about cooling the barrel and pressing a sleeve on it. i could see that tightening up a bore.

 

[1813Benny]

Adding stress to a rifle barrel is not good. There is a reason the major (and successful) barrel makers have a thorough heat treatment /stress relieving process.

 

[RTH1800]

Adding stress to a rifle barrel is not good. There is a reason the major (and successful) barrel makers have a thorough heat treatment /stress relieving process.

This is true. What we are talking about here is an attempt to improve a barrel that is going to be removed and replaced. A last ditch effort to save a barrel.

 

[1813Benny]

This is true. What we are talking about here is an attempt to improve a barrel that is going to be removed and replaced. A last ditch effort to save a barrel.

I understand the intent, but the likely results of the effort, combined with time and cost might be not worth the effort vs new.

If you are trying to salvage a barrel, cut off 3” at the breech and rechamber and cut .100” off the muzzle and recrown. If it doesn’t improve, move on…

 

[RTH1800]

OK, I'll put you in the no column.

 

[MarkCZ]

I’m not a machinist or gunsmith.
I have long wondered about “fixing” less than stellar rimfire barrels.
There is a school of thought that a small amount of “choke” aids in accuracy. Why not utilize some type of hydraulic compression to the muzzle to build in a tenth or two of “choke”? (.0001 - .0003)This for a barrel that simply is not preforming as well as we would like but otherwise appears fine.
Would it take more pressure than could be readily applied?

Anything you add to the muzzle with act like a tuner with no adjustment. Get a Harrell bolt on tuner. A tuner will get the barrel shooting the best it can.

 

[RTH1800]

I am aware of the above suggestions. Common knowledge.
Looking for input on my thoughts.

 

[jbell]

I am aware of the above suggestions. Common knowledge.
Looking for input on my thoughts.

It would be interesting if you reached out to a few barrel makers and get their thoughts. If you do please post them here...

@Frank Green

 

[RTH1800]

I realize that some barrels have poorly cut chambers, poorly cut crowns, bore damage or plain just not well made.
I also realize that tuners, re crowning, re chambering etc can sometimes fix an issue. My question is once these options are exhausted or ruled out why not tighten the muzzle and see what happens. Not expecting miracles, just curious if anyone has tried it.

 

[68hoyt]

I was going to pm you but ,,,,,,, I agree , what do you have to lose , it shouldn’t cost much if you have resources , make a interference fit sleeve allowing for the barrel to be cold and install , about 3-4” long ? If it doesn’t work ,,,,,,, at least you know , I would like to know what happens as I’ve wondered the same thing

 

[justin amateur]

I can decrease the barrel diameter, but can I do so
in a way so as to produce an even taper, not distort the rifling
and not create stress lines in the steel that will show when heated?

I don't think I can.

 

[68hoyt]

Make a tapered sleeve so that it doesn’t make a hard line in the rifling ?

 

[Frank Green]

I’m not a machinist or gunsmith.
I have long wondered about “fixing” less than stellar rimfire barrels.
There is a school of thought that a small amount of “choke” aids in accuracy. Why not utilize some type of hydraulic compression to the muzzle to build in a tenth or two of “choke”? (.0001 - .0003)This for a barrel that simply is not preforming as well as we would like but otherwise appears fine.
Would it take more pressure than could be readily applied?

Nice thought but I feel you’re going to deal with another problem. If it’s a button rifled barrel and depending on the diameter of the muzzle and depending on how much you plan to turn off for a press fit sleeve the bore could change/open up more on you.

Either way how much of a press fit will you need to tighten the bore up say .0003” to .0005” from where it is now?

Which brings up another question? What is the actual bore size and the actual groove size? I think you would need to know this before diving into it.

If button barrel does it have a uniform twist?

Is the barrels bore and groove actually have a negative taper? Tight at the breech and getting bigger as you go towards the muzzle end.

As has been mentioned, quality of the chamber, crown, bore finish etc… you think you might be fixing a problem but your problem might some where else?

Later, Frank
Bartlein Barrels

 

[David Nissen Kahn]

Like the questioner, I'm neither gunsmith nor engineer, just interested lurker trying to learn. So...in the line of "what is there to lose," what about this? I'm assuming that the barrel was installed by someone who chambered correctly with a quality reamer, properly did the muzzle crown, and so on. It seems to me that barrel length beyond ~16 inches for a 22 rimfire is for balance, esthetics, or, in the case of long range, benefits found with lengthier barrels (that I'm not sure I understand). If the barrel length is what's wanted, slug the bore to the tight node nearest the muzzle, then bore the barrel out to that point and finish the (now hidden) muzzle there. The opened-out section distal would then work as a "bloop tube" or, say, could be machined out for a muzzle device, though the utility of that on a standard-velocity rimfire with a heavy barrel seems illusory beyond esthetics. Or it could be used as the place to mount a tuner, I suppose. There've been some notes, in this forum or elsewhere, that suggest turning down the barrel at the muzzle and threading for an attachment can be detrimental to accuracy. Some rimfire gunsmiths that knowledgeable people in the Hide respect won't install one if they can avoid it. Benchrest guys seem to prefer a bare muzzle, and them's the folks as oughta know.

As I say, I'm not qualified to know. What do you folks think?

dk

 

[Frank Green]

Like the questioner, I'm neither gunsmith nor engineer, just interested lurker trying to learn. So...in the line of "what is there to lose," what about this? I'm assuming that the barrel was installed by someone who chambered correctly with a quality reamer, properly did the muzzle crown, and so on. It seems to me that barrel length beyond ~16 inches for a 22 rimfire is for balance, esthetics, or, in the case of long range, benefits found with lengthier barrels (that I'm not sure I understand). If the barrel length is what's wanted, slug the bore to the tight node nearest the muzzle, then bore the barrel out to that point and finish the (now hidden) muzzle there. The opened-out section distal would then work as a "bloop tube" or, say, could be machined out for a muzzle device, though the utility of that on a standard-velocity rimfire with a heavy barrel seems illusory beyond esthetics. Or it could be used as the place to mount a tuner, I suppose. There've been some notes, in this forum or elsewhere, that suggest turning down the barrel at the muzzle and threading for an attachment can be detrimental to accuracy. Some rimfire gunsmiths that knowledgeable people in the Hide respect won't install one if they can avoid it. Benchrest guys seem to prefer a bare muzzle, and them's the folks as oughta know.

As I say, I'm not qualified to know. What do you folks think?

dk

After 16" there is no more powder to burn in a 22RF. So the only thing a longer barrel in RF does is weight and balance... a longer sight radius if shooting open sights.

To my knowledge all RF match ammo is already subsonic and you don't want it breaking the speed of sound.

Some of my scoped guns I'm only running a 18" to 21" barrel. Yes I've got a bloop tube on one of my position rifles which that barrel length is 21" but shoot it primarily scoped. If I want to put irons on it... I put the 6" bloop tube on it.

 

[RTH1800]

I have found longer barrels unsuppressed to be MUCH more quiet than suppressed 16-18” barrels.
I my experience they also seem to deliver more uniform (and lower) velocity.
My 28” Win 52’s are less noisy than a suppressed 16” barrel.

 

[DFOOSKING]

I have found longer barrels to me MUCH more quiet than 16-18” barrels.
I my experience they also seem to deliver more uniform (and lower) velocity.
My 28” Win 52’s are less noisy than a suppressed 16” barrel.

Is that because its in fact quieter? Or because the report is physically further away from your ears? Or both(?)

I wonder if someone could actually measure it.

My 52B is quiet as well. But nowhere as quiet as my 21" suppressed 77/22 in its prime. Obviously the can helps....just saying they aren't really comparable. One being good and the other being great.

 

[RTH1800]

My KIDD 18” suppressed is loud compared to my bare 28” 52’s.
I would say both distance and actual report make it quieter.
The KIDD barrel is so slick it must be supersonic with Eley Match ammo. I hear a sharp crack.

 

[Charger442]

i would assume any type of tapered sleeve to compress the bore would probably do more to change the barrel harmonics than actually constricting it. and i think there would be your accuracy or lack thereof.

 

[Sum Ting Wong]

When I was machining for a PCP airgun company, we tried to add a choke to new barrels. Nothing we tried in house had an affect on bore diameter. We never tried a multi die hose crimper, but you’d need a custom set of dies as most crimp in a slight hex shape. You have to remember that you’re trying to compress an almost solid bar of steel, and do it uniformly.

 

[Seymour Fish]

I’m not a machinist or gunsmith.
I have long wondered about “fixing” less than stellar rimfire barrels.
There is a school of thought that a small amount of “choke” aids in accuracy. Why not utilize some type of hydraulic compression to the muzzle to build in a tenth or two of “choke”? (.0001 - .0003)This for a barrel that simply is not preforming as well as we would like but otherwise appears fine.
Would it take more pressure than could be readily applied?

if
If you have a “problem bbl”, easy to attempt to taper-lap it with diamond paste on a VFG pellet. Nothing to lose.

 

[Merlin O]

Crush choking a steel rod...? IMO... Be more successful meeting at the crossroads by the graveyard during the full moon and making a blood sacrifice of a horned lizard while chanting Calfee, Calfee, Calfee to the dark gods of rimfire accuracy. Of course I developed this theory by drinking Mogan David 20-20 and casting chicken bones in a pentagram behind the pool hall....

 

[jbell]

Crush choking a steel rod...? IMO... Be more successful meeting at the crossroads by the graveyard during the full moon and making a blood sacrifice of a horned lizard while chanting Calfee, Calfee, Calfee to the dark gods of rimfire accuracy. Of course I developed this theory by drinking Mogan David 20-20 and casting chicken bones in a pentagram behind the pool hall....

Haha, so you don’t think Bill would recommend it as a possible solution? I sure do miss his writings and have always wanted one of his builds…

 

[Merlin O]

Love or hate he is forever a piece of rimfire history....

 

[Rider47]

As a true last chance/Hail Mary attempt, and if you have nothing to lose except personal effort - why not? I have found almost any constriction on the outside of the barrel will change the internal dimension (and the reverse, removing metal for threading opens up the bore), so . . . Probably not difficult to machine a clamp device with tightening screws, just like the attachment end of a clamp on tuner. This might be difficult if you have a tapered profile, I'd make it about 1.5-2" or so in length. But worth the effort to machine up something? Personal decision. Personally If I'd truly exhausted all other alternatives, I think I'd focus on another barrel.

BTW - I machined a bushing and placed it in my Harrell's tuner on my ARA BR competition rifle such that the tuner clamp tightened on the last ~1" of barrel, instead of ~3/4" back from the muzzle as designed. I saw no improvement in precision and eventually removed the bushing and moved the tuner back into its designed position.

 

[BMP]

I have found longer barrels unsuppressed to be MUCH more quiet than suppressed 16-18” barrels.
I my experience they also seem to deliver more uniform (and lower) velocity.
My 28” Win 52’s are less noisy than a suppressed 16” barrel.

My KIDD 18” suppressed is loud compared to my bare 28” 52’s.
I would say both distance and actual report make it quieter.
The KIDD barrel is so slick it must be supersonic with Eley Match ammo. I hear a sharp crack.

If you are hearing any noise at all with a suppressor on, the bullet is going supersonic. My 26" Lilja is quiet but not suppressor quiet.

Brad

 

[RTH1800]

If you are hearing any noise at all with a suppressor on, the bullet is going supersonic. My 26" Lilja is quiet but not suppressor quiet.

Brad

Undoubtedly, that is my point. Some short barrels are transonic with match ammo.