rechamber

[liseo]

Hello everybody.

After about 1650 shots, i´m thinking to remake the chamber in my 6PPC.
How many inches should I cut to rechamber? The barrel is Krieger 24 inches long now.

 

[Preacher]

First you need to know how far the throat has advanced........
Remove just enough metal so that you will clean the old throat up
and you get back into good rifling.......

 

[fdshuster]

liseo: I'm doing just that with a 24" Shilen 6ppc. "Measured" the length of the bore surface that showed even the slightest fire-cracking, using my "Hawkeye" borescope, and determined that it's 3 1/2" in front of the chamber mouth, so the 'smith is shortening it to the now standard 20", that will put it well ahead of the damaged area. Total rds. fired is 2410, from a log book kept for the rifle. Throwing an occassional flyer from an otherwise excellent 5 shot group, and more difficult to remove the copper. Time to set it back, this time with a .272" rather than .262" chamber neck.

 

[liseo]

Preacher

Unfortunately I do not have the Hawkeye borescope.
And even if I had, the experience to evaluate the results ;D

fdshuster

How far of the groups were the flyer?

My barrel still dont show any copper evidence, but ...

Thanks

 

[fdshuster]

liseo: Many gunsmiths, that I know, are using borescopes now, so maybe they could take a look, but at 1650 rounds fired your "damage" should be less than mine is at 2410. 5 shot groups at 200 yd. would easily hold 1/2" to 5/8" when the barrel was in it's prime, but last Summer the occassional, unexpected flyer ( always happened in a match) would open it up to 3/4" to 1". Copper fouling did not become a problem on mine either 'til I hit around 2000 rds. fired. After this barrel is set back & rechambered if it's successful, a new Krieger blank is standing by to be cut with the same reamer, left at 24", and setup as another switch-barrel. This rifle really came alive last Summer after I installed a McMillan Edge stock, so have been shooting it a lot more: has become my first choice for 1 & 200 yd matches for score ( g'hog). Use the 6BR's for further distances.

 

[sharps]

Frank, Just read your input on bbl life and rechamber and I too have experienced un-expected flyers during a match and always thought it was me!!! This makes me feel a lot better as now in my most quiet moments I now know the barrel done it.....not me even though you could stick a Hawkeye in my ear and plainly see
my old brain is really eroded and firecracked

 

[fdshuster]

sharps: Yes, the "Hawkeye" has been a real eye opener, coming up on 4 yrs with it now, and I continue to learn. Firecracking in itself would not cause me much concern, I have other barrels with varying degrees of cracking & they continue to shoot, but when it includes the unexplained flyers, to the point you cannot depend on the rifle any longer, and more copper fouling than previous, I start looking for a fix/replacement. So far, set backs have worked fine, giving me "double the life". Another reason I prefer the heavy contoured straight taper, starting at a minimum of 24" or 26" oal, and the gunsmith cuts my chambers with my own spec'd reamers, from Pacific.

 

[liseo]

Based in your experience, what of these barrels is probably more worn out?
The Krieger 6 PPC at 1650 rounds .
The krieger .308 Winchester at 2600 rounds .
Both barrels had never become to hot and were cleaned carefully.

 

[fdshuster]

liseo: As long as both are producing groups to your liking, I would keep shooting them 'til you feel accuracy (or the lack thereof) is becomming a problem, and about the same time re-evaluate the amount of copper fouling and how difficult it is to remove. The 6ppc may be ready around 2K to 2200, but who can say for sure? Kevin Thomas did an exhaustive multi-page article for "Precision Shooting" magazine in the September 1998 issue titled "Meanwhile, 17224 rounds later" in which he fired 4 different 308 chambered barrels in very controlled conditions, a total of 17224 rounds, and they all started to deteriorate around 3800. By 4000 or shortly after, they were all ready for the scap bin. With that in mind then, your 308 has approx. 1400 rds. remaining, (probably mine too)/ 545 thru mine, so a good long way to go.

 

[X Ring Accuracy]

OK, I will take a stab in the dark to answer his question....I will say remove 1 inch. For a rechamber job, a starting point is to cut off the barrel where the tenon starts. Flame suit on

 

[sxsboy]

FDS
[/quote]Time to set it back, this time with a .272" rather than .262" chamber neck.[/quote]

Why are you adding .010" to the neck? I'm just curious. Are you going to - no turning the necks on your cases? It just seems like 10-k is alot from what you have/had. It's my understnding that you benchrest guys like things as tight as possible in the neck area.
I'm like an old dog wondering about new tricks

 

[Preacher]

Not to many folks using a .262 neck anymore, most have discovered that a no turn will do as well.. I like a .269 neck these days, so I can just do a clean up cut and get on with it...

 

[fdshuster]

sxsboy: Preacher said it well. After spending 11 years turning 220 Russian case necks down to a paper thin .0085", and throwing all the cut-off chips into the garbage can, decided there just might be a better way, especially when I also see others shooting top scores with no-turn, and tight fitted necks done with only a minimal clean-up cut. In preperation for the new chambering (the 'smith called last night and said "bring the rifle"), I just outside neck turned new Lapua 220 Russian for the new chambering to a neck wall thickness of .0132", measured with my tubing mic, for a loaded round neck dia. of .2694", chamber neck dia. of .272", so I have the same amount of clearance, but with thicker necks. At the time the rifle was built (1998), 24" barrels were the "standard", and now there are more 20" being used ( and winning, also proving that also works), so setting back the heavy varmint contour was an easy choice. This rifle is being set-up as another switch-barrel, and after working with the new chambering/"old barrel", a 24" Krieger heavy contour will be cut with the same .272" reamer: 1 receiver, 2 barrels. So many choices.

 

[bandit10-4]

I would say 1" off of each end