Question on Barrel Set Back / Barrel Wear / and Powder.

wlleven · 11-22-2013, 05:31 AM

I'm not a real competition shooter, but have a question or two about barrel wear that I'm sure you competition shooters can answer.

When you have to set back your barrels, how far is that, are we talking .200 up to maybe .400 ?

Also, after you have set back you barrel maybe once or twice, does the barrel itself get worn out because of friction ? I know that eventually it will loose its rifling and start to fade, but with one or two set backs are you still OK ? I'm talking about cartriges in the PPC to 6.5x47 class, I realize that an over bore cartridge will greatly speed up your need to set back or possibly get a new barrel.

Also, there has been theories on ball powder vs stick powder on barrel wear, in your experience have you guys found one over the other gives better barrel life ?

Thanks guys.

wll

stangfish · 11-22-2013, 07:38 AM

Eventaully the throat wears. Cracks start to propagate and erosion increases the diameter of the lands. To set back a savage barrel you need to have enough of the thread diameter on the OD to have room for the barrel nut(unless you are using a barrel nut delete type tube). A bore scope or chamber cast might tell you how much needs to be removed to minimize the amount of setback is required to get to fresh rifling. Anything else would be random weather appropriate or not, while I am certain some smiths have an amount the smith usually goes by. Asking yours would be a good place to start. On longer barrels some even remove about 3/4"-1" off of the muzzle end as well .

wlleven · 11-22-2013, 11:06 AM

Originally Posted by stangfish

Eventaully the throat wears. Cracks start to propagate and erosion increases the diameter of the lands. To set back a savage barrel you need to have enough of the thread diameter on the OD to have room for the barrel nut(unless you are using a barrel nut delete type tube). A bore scope or chamber cast might tell you how much needs to be removed to minimize the amount of setback is required to get to fresh rifling. Anything else would be random weather appropriate or not, while I am certain some smiths have an amount the smith usually goes by. Asking yours would be a good place to start. On longer barrels some even remove about 3/4"-1" off of the muzzle end as well .

Thanks Stangfish,

I'm building my first build and was just wondering.

wll

82boy · 11-22-2013, 11:37 AM

There is many things that happen in the life of a barrel, cleaning rods, and the natural affect of firing the rounds will cause wear on the throat and lead in of a chamber. As the barrel is fired the chamber may grow and to keep on top of accuracy a shooter may have to re-adjust there seating depth as the barrel goes on. Fire cracking is a condition, that may or may not affect accuracy. What a shooter is attempting to do when they re-chamber a barrel is to bring it back to the state it was at earlier in its life. They may or may not have any fire cracking, but they may just want to make sure that the rifling is good and sharp at the chamber. If you figure this the barrel may have a lot of life still in it, it is just that it needs a fresh start to get things back into proportion.

When dealing with set back and re-chambering, there is too schools of thought one is to bring life back into a barrel, the other it to maintain a barrel at it utmost accuracy. Some short range Benchrest shooters will set back the barrel every 100 or so rounds. They only cut a small amount off like a couple of thousands, and run the same reamer into the chamber, and put it back into speck. These guys are also ultra competitive, and will more than likely throw a barrel out at 700 rounds. Some will never re-chamber a barrel as they don't believe it is worth the effort. Most 6PPC barrels will shoot competitively up to 4000 rounds. There are accounts of people with high round count barrels winning match's. It is a personal preference.

Many long range shooters will buy barrels extra long so that they can cut the entire chamber off, and re-chamber the round. They may do this ever 500 to 1000 rounds down the barrel. They may re-chamber the barrel 4 or 5 times before they give up on it.

When I have a barrel re-chambered I do so, as it is getting close to 1000 rounds, I want to freshen things up. My gunsmith has a bore scope, and I have him cut it off at the point where he can get a fresh chamber. This may be 1 thread, it may be a 1/2 inch, and it may be more. I want clean material to work with. Many times a barrel will go back to shooting if accuracy falls off, but a re-chamber is no guarantee, It is possible the barrel is shot. I will have the barrel set back and re-chambered once, and if it is still going, I let it go, as I figure it is time to get a new barrel.

Many people don't set back and re-chamber a barrel due to cost, your going to pay a smith at least $100 to do this, and as said before there is no guarantee it will help. If you got a barrel that is just an outstanding performer, it might be a good idea, but when you can get a pre-fit barrel for such little cost , if the barrel was never outstanding then why bother.

**sharpshooter** · 11-22-2013, 01:52 PM

Typically it takes about 13-14 lbs of powder to kill the guilt edge accuracy of most barrels, no matter how many times it's rechambered.
I've found that most shooters that worry about barrel life will never shoot that much.

stangfish · 11-22-2013, 05:34 PM

Great post 82boy and good input Fred.

[I've found that most shooters that worry about barrel life will never shoot that much.

Thought provoking

**missed** · 11-22-2013, 07:14 PM

I have found it cost prohibitive, especially with the barrel nut and the pre fits available now. I have only shot out one 308 barrel and one 22-250 barrel I had TONS of ammunition through them, the 308 barrel I replaced and the 22-250 I had chambered and crowned and it bought me some more rounds through it but the accuracy faded faster and if I do it again I'll just buy another pre fit.

wlleven · 11-23-2013, 06:09 AM

Guys,

Thank you so much, you are all a fountain of info.

Sharpshooter, you are correct, I will probably never shoot out my barrel, I just worry about those things.

My new build in 6.5 Grendel with a 28" barrel I'm sure will have a very long life. When I go to the range I don't think I've ever fired over 15-20 rounds per rifle in a days work, and as it stands now I maybe go twice a month. More often then not I go to sight in using the two shot method, velocity is checked on my chronograph to see I'm getting the speed I'm after, and maybe shoot 5-10 more shots at a gong. I will do a 3 shot group to check that things are going well though ;- )

When working on a load I check all the charts, talk to everyone and then decide on what powder is giving the highest velocity and accuracy. Most of the loads I have are in the upper 90+% as far as velocity goes .. I'll push them, but not at the point of flattened primers, ejector marks, tight extraction, etc.

The other thing I never do is shoot fast, it will take me 5-10 minutes between shots when I'm shooting, I never just keep loading and send lead down range.

Most of the hunting I have done is varmint hunting, with an occasional hog thrown in ;- ) Of the varmint hunting I usually take my time and sit a bit between shots also.

As far as big game, I do plan on hog hunting a bit next year.

wll

**sharpshooter** · 11-23-2013, 10:47 PM

When you get bored with that 28" barrel, start cutting it off an inch at a time, chronograph and tweak the load to the new barrel length. You will be surprised at the education you'll get.

wlleven · 11-24-2013, 03:10 AM

Originally Posted by sharpshooter

When you get bored with that 28" barrel, start cutting it off an inch at a time, chronograph and tweak the load to the new barrel length. You will be surprised at the education you'll get.

Yes, I'm sure you are correct, there is a sweet spot for barrel length, is the extra velocity worth the extra inches of length ? - portability, balance and weight do become an issue. Sometimes more is not always better, I will find out with this build for sure !

As an example, I was surprised at the velocity my 20" Hog Hunter in 308 gave me, It really doesn't loose much in velocity but gains a whole bunch in portability.

wll