[bga71]

Received the rifle yesterday, cleaned thoroughly and measured bolt gap at .009. Today I fired 100 rounds of m855, cleaned rifle tonight and measured bolt gap, again at .009. How many rounds to determine if I'll have problems with shrinking bolt gap due to improper barrel pressing/pinning?

 

[usmc_mwroseberry]

Mine showed its ugly issue within the first 120rds. I'd say if yours hasn't run away by now it may not. If I was you I'd get a size larger rollers than you have now which should put you up to about .011 or so and shoot it until it drops back down below .008.

Sounds like you got lucky.

Good luck,
Merritt

 

[hkshooterusp]

I agree. Most reports say that 100 rounds was enough to lower the gap. Go burn another 100 and check it. If it's good, yeah, you got lucky. Enjoy your rifle.

 

[jfk]

Received the rifle yesterday, cleaned thoroughly and measured bolt gap at .009. Today I fired 100 rounds of m855, cleaned rifle tonight and measured bolt gap, again at .009. How many rounds to determine if I'll have problems with shrinking bolt gap due to improper barrel pressing/pinning?

The gap is dependent on several factors, how much material the builder decided to take off the barrel to get an easy press fit, how much slop in the barrel pin hole, and what the gap was set by the builder. Your barrel may hold up to a few hundred rounds before it settles. Sight your gun in and shoot it. After 1,000 rounds, check the gap or when it begins to malfunction.

 

[boystcroix]

My C93 started with almost no bolt gap and after 120rds it had absolutly none. Check your barrel pin, I was able to tap mine almost all the way out with a few light taps of hammer and punch. I ended up sending mine to Ghillie with a new barrel.

 

[bga71]

OK, after 200 rounds total, rifle has been cleaned again and measured bolt gap, and it's still at .009. I bought a caliper today to measure the rollers, and they both measure 7.98 mm. If I put +4 rollers in, should that give me .015 bolt gap?

 

[usmc_mwroseberry]

should be right about there from everything I've been reading. give the rollers a try and make sure every time you take it out to shoot it clean and check it. Ghillie just replaced my barrel and I still keep track of it.

Good luck,
Merritt

 

[boystcroix]

you might want to use micrometer to measure rollers, I found calipers are not accurate enough

 

[Shattered Mind]

you might want to use micrometer to measure rollers, I found calipers are not accurate enough

Huh? Even my old pair of cheapy plastic calipers I bought waaaay back in the '70s for reloading are accurate enough for that. Mebbe you need to learn how to use them.

 

[hkshooterusp]

Huh? Even my old pair of cheapy plastic calipers I bought waaaay back in the '70s for reloading are accurate enough for that. Mebbe you need to learn how to use them.

Glad I'm not the only one who scratched his head when he read this.

 

[boystcroix]

my digital calipers that i measure small reel bearings are not accurate enough when trying to read to 1/100 of a mm so i had to use a micrometer to be sure of roller size i doubt that cheap plastics arethat accurate

 

[Blitzkrieg]

.009 is kinda low, consider +4 rollers after you figure out if it's a problem child or not

 

[Shattered Mind]

my digital calipers that i measure small reel bearings are not accurate enough when trying to read to 1/100 of a mm so i had to use a micrometer to be sure of roller size i doubt that cheap plastics arethat accurate

Plenty good enough to measure rollers...

Amazon.com: RCBS Plastic Dial Caliper: Sports & Outdoors