Precision barrel making

[Cat Whisperer]

Perhaps a little far out from the norm here, but of interest as we've discussed straightness of barrel making before:

http://www.manufacturing.net/articles/2012/03/one-hole-wonder?et_cid=2537898&et_rid=372537280&linkid=http%3a%2f%2fwww.manufacturing.net%2farticles%2f2012%2f03%2fone-hole-wonder

[KABAR2]

   And to think in Gunsmithing school we would look down the bore for straightness and if it was off a little to one side take it out back to a chunck of tree trunk and give it a wack .... look down it and see if the issues was corrected.... who would a thunk....... 
 
   Hey! It worked for P.O.Ackley.....

[GGaskill]

But Ackley wasn't a match barrel maker. 

It will be interesting to see if these techniques are adopted by the high end barrel makers.  That will be the ultimate measure of correctness.

[KABAR2]

But Ackley wasn't a match barrel maker. 

It will be interesting to see if these techniques are adopted by the high end barrel makers.  That will be the ultimate measure of correctness.

No but he was interested in accuracy and ballistics...... Most likely we will also see these barrels making their way into the sniper pond........ remember he is talking match performance out of a semi-auto rather than boltaction.......

[shred]

I don't get why this doesn't apply to high-end Bolt-Action Olympic Race Rifles, whatever they are.  A better barrel is a better barrel.  A little embellishment on the part of the journalist perhaps.

The interesting thing is the air-rifle guys are far more accurate than the powder-rifle guys... I doubt they have seriously better tubes, so maybe the barrel isn't the entire problem?

[GGaskill]

I don't get why this doesn't apply to high-end Bolt-Action Olympic Race Rifles, whatever they are.



This isn't an Olympic rifle (it's for NRA across the course matches) but it is an example of what he is referring to.  I guess he chose to stick with 10/22's because they would show a more dramatic improvement than something that already shoots half minute groups.  Read this article for more info on the rifle.

The interesting thing is the air-rifle guys are far more accurate than the powder-rifle guys... I doubt they have seriously better tubes, so maybe the barrel isn't the entire problem?

I read some time ago that the records of Remington 40X construction and testing leave no doubt that as the power of the cartridge increases, the accuracy decreases.  No explanation was given but my personal opinion is that bullet distortion increases as power increases and that is where most of it comes from.  I suppose that firing time wave patterns and amplitude may also come into play.

[Double D]

Do they make barrel for a parrot rifle?

[GGaskill]

Do they make barrel for a parrot rifle?

6mm BR ought to do a dandy job on parrots if they are in season and can be hunted with a rifle.

I suppose you could make a 1/6 scale one using a .50 cal barrel.

[Double D]

But Ackley wasn't a match barrel maker. 

It will be interesting to see if these techniques are adopted by the high end barrel makers.  That will be the ultimate measure of correctness.

We are so far of topic here I will just go ahead and continue.  Ken Erdman won the 1982 and 1983 National Service rifle championships with a Garands using barrels made on P.O. Ackley rifle barreling equipment.  Just to pat my self on the back, I was part of the build team for the 1983 rifle.

I have a barrel made on Ackleys equipment and chambered in .219 Donaldson Wasp that has fired a 3 shoot group under .138" at 100 yards.   Ackley inspected that barrel and then handed it tme and said that barrel is going to be a good shooter...Ackley made a lot of  Match barrels. 

The bench rest  a punching some very impressive very small and close to ne hole groups already.  True Benchresters would just yawn at such large .138" group.

There have seen a number these new process for rifle boring that have come along over the years.  Some work, others are just hype. Is this hype or will it really work...only time will tell...and I hope these guy never give up trying because this hobby would get boring real quick if they did.

[GGaskill]

Bench rest and mid-range (600 yards) and long-range (800-1000 yards) are mostly wind reading sports and don't really measure the capability of the barrels.  Most people don't have underground ranges (the reason I bought my current property although I never built the range) or Houston warehouses to test in windless conditions so we really don't know how good the best barrels are, and they are limited by the quality of the bullets anyway.

The best bench resters shoot five or ten shot groups in the teens in the open.  Not much left to go.

[Victor3]

 I wish him well, but I've gotta wonder about a few things...
 
 Why did he pick .22 mag (let alone in a 10/22) to show his bbl's accuracy? No match-grade factory .22 mag ammo is available, so ammo related variables will show themselves. I suspect his groups had to have been cherry picked, even if he shot them in a vacuum chamber. He would have garnered a bit more credibility had he used a bolt action match rifle & ammo in .22 lr.
 
 The article says he's drilling/reaming/honing "barrel blanks." Doesn't matter how straight/round/consistent in diameter a hole in a blank (no matter how well the material is stress-relieved) is if it's button rifled and machined on the OD subsequent to the hole-making process. Button rifling/machining introduces & relieves stress in the material that will distort diameter/roundness/straightness that will negate some of the precision of the initial hole.
 
 He claims he wants to acheive "successive bullets through the same hole, using an inexpensive semiautomatic rifle." That would be nice and all, but unless the target is 3" from the muzzle it isn't going to happen very often. Too many variables not related to precision of the bore come into play.

[Artilleryman]

So how do we relate all of this information to making a more accurate artillery barrel? 

[Cat Whisperer]

Yes, that's why I posted it.  It relates to improving the accuracy of gun drilling and tweeking the process for better accuracy of drill.

[Victor3]

So how do we relate all of this information to making a more accurate artillery barrel?

 Apart from bbls incorporated into some sort of "bench-rest" cannons (which would require precise mounts, optics, precision charges, projectiles mated perfectly to the bore, etc.), it would be difficult to determine accuracy differences between a good bore and a great one.
 
 But what the heck.... Like a doctor performing CPR on a decapicated patient said, "it couldn't hurt."