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Need pressure schooling !

Dusty Stevens said:
Never anything on a brush but solvent. Use a pierce style jag. For a 6mm i use a 22cal jag with a 1 3/4” square proshot patch.
Click to expand...

Now I’m confused !

I got in there with a bronze brush and cleaned it out real good . No black is coming out with the C4 . Here’s the strange part . I went to chamber a round and it felt like I was jamming into the lands .005 or .01 . Took cartridge out and it looks like rifling marks on bullet . I’ll send u a pic in a little bit . WTF ?
Chambered another round that was seated .02 deeper and no marks whatsoever and no seating pressure .
 
Last edited:
SavageMark said:
Now I’m confused !

I got in there with a bronze brush and cleaned it out real good . No black is coming out with the C4 . Here’s the strange part . I went to chamber a round and it felt like I was jamming into the lands .005 or .01 . Took cartridge out and it looks like rifling marks on bullet . I’ll send u a pic in a little bit . WTF ?
Chambered another round that was seated .02 deeper and no marks whatsoever and no seating pressure .
Click to expand...

Sounds like youre exactly on the lands now instead of the carbon ring. Thats good news
 
If you have carbon on the lands your grooves, the bore diameter, is probably a black ceramic-like carbon deposit. That primer blanking you show is common when carbon deposits get in the bore. Just seems the 6BR variants are the worst for that. C4 is useful but not the real answer.

The real answer is a borescope to see where you are. Then it may be decision time to scrub the mess repeatedly. Even the serious chemical I use does not work on that ceramic groove deposit. It takes horrible scrubbing with abrasives and then just maybe - give up and get a new barrel.
 
CaptainMal said:
If you have carbon on the lands your grooves, the bore diameter, is probably a black ceramic-like carbon deposit. That primer blanking you show is common when carbon deposits get in the bore. Just seems the 6BR variants are the worst for that. C4 is useful but not the real answer.

The real answer is a borescope to see where you are. Then it may be decision time to scrub the mess repeatedly. Even the serious chemical I use does not work on that ceramic groove deposit. It takes horrible scrubbing with abrasives and then just maybe - give up and get a new barrel.
Click to expand...

So you’re saying only some barrels show this mess ???? If that’s true I’ll send it back to Shilen .
 
Instead of using jags and patches for iosso, I usually use these:

https://www.midwayusa.com/product/1255143899

There are several brands, and I usually find them locally for less than $2. They work really well by smearing the iosso on them with your finger and rolling it around. They are easy to work back and forth in a small area and seem to get into the grooves in the rifling pretty well. You could probably reuse them but they will be a black gooey mess quickly, so I use a new one every time.
 
oldduc said:
Instead of using jags and patches for iosso, I usually use these:

https://www.midwayusa.com/product/1255143899

There are several brands, and I usually find them locally for less than $2. They work really well by smearing the iosso on them with your finger and rolling it around. They are easy to work back and forth in a small area and seem to get into the grooves in the rifling pretty well. You could probably reuse them but they will be a black gooey mess quickly, so I use a new one every time.
Click to expand...

So there’s less pressure .01 out of the lands than .01 into the lands correct ?
 
Internet & quickload has a bullet jammed adding 10,000 PSI?

Hodgdon data has 6mm br Rem with 107 Sierra at 29 grs Varget maximum.

Your primer flow looks like a CCI 400 primer?

I dont have one, dont load one , just saying. :)

I dont see a listing by SAAMI, when looking for maximum psi? Still a wildcat?

2- Rem & Norma?

Sierra load data. 20190824_094127.jpg from https://www.6mmbr.com/6mmbr.html

Screenshot_20190824-094444.jpg
 
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243winxb said:
Internet & quickload has a bullet jammed adding 10,000 PSI?

Hodgdon data has 6mm br Rem with 107 Sierra at 29 grs Varget maximum.

Your primer flow looks like a CCI 400 primer?

I dont have one, dont load one , just saying. :)

I dont see a listing by SAAMI, when looking for maximum psi? Still a wildcat?

2- Rem & Norma?

Sierra load data. View attachment 1122557 from https://www.6mmbr.com/6mmbr.html

View attachment 1122558
Click to expand...
Yes , tough to find load data for 6BR Norma ! The classic load is 30g Varget with 107 . I’ve read where some say they don’t notice a pressure difference in or out of the lands but I sure did today . Had a very sticky bolt in the lands . Seated bullet .02 deeper and what a difference . Wife shot all 50 rounds and didn’t complain once about bolt lift . Hopefully things will get better now ! Thx everyone for all the help !
 
SavageMark said:
Yes , tough to find load data for 6BR Norma ! The classic load is 30g Varget with 107 . I’ve read where some say they don’t notice a pressure difference in or out of the lands but I sure did today . Had a very sticky bolt in the lands . Seated bullet .02 deeper and what a difference . Wife shot all 50 rounds and didn’t complain once about bolt lift . Hopefully things will get better now ! Thx everyone for all the help !
Click to expand...

If you go buy a very recent jug of varget beware of 30.0!!! Better start at 28 and dont load up a lot past 29
 
Should be safe. Just dont go with the standard 30.0 and go with recent varget lots. If it was on the gun store shelf for 6mo itll be fine. It has changed and needs to be tested. @joshb warned me and sho nuff its hotter than normal
 
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