6BRX fire forming, what went wrong ?

[fm1947]

Sa you can see 45 formed okay 5 did not form a shoulder, what's your thought, I'm thinking try again on those 5

 

[7stubby]

What is your fireforming load your using?

 

[fm1947]

What is your fireforming load your using?

30 grs varget

 

[dfry]

Using false shoulder, jambing, or both?

 

[fm1947]

Using false shoulder, jambing, or both?

JAM ! 45 cases were good 5 were not

 

[tonysnoo]

Did you look at them real close with a magnifier?

We had a bunch hydro formed and the ones that split looked just like your rounded ones

 

[fm1947]

Did you look at them real close with a magnifier?

We had a bunch hydro formed and the ones that split looked just like your rounded ones[/QUOT

No cracks, just used magnifier

 

[dfry]

If the cases look fine, shoot them again. The way I do it, and I stress, the way I do it, others may have their way, is I set my sizing die where I want it to load my formed brass with the proper shoulder bump I want and use both false shoulder and jamb. I know, repetative but that way I dont have to mess with adjusting my sizing die continually. Then use a smaller bushing for a tight neck and jamb .030 and load 30.2 grs of Varget. Ocassionally i will get a case that doesn't form completely, but not often this way. When I do, I size and fire again.

Also, if you can anneal first, it cuts down on split brass, especially if its not new brass.

Dave

PS: 105-108 weight bullets, and I form during a match, they shoot just fine!

 

[swd]

Shoot em' again. No harm no foul. Maybe go up half a grain. I fire form with 30.5 Varget, 107 SMK .050" in the lands, Winchester SR with the ejector removed. I've never lost a single one and the come out great.

 

[fm1947]

I'm doing that right this minute , working FINE

 

[dmoran]

I suggest to measure those that your hitting a 2nd time very closely, in comparison. Any that do not blow out to within .004" of the others in length, I myself would cue out.

Good fire-forming to me is more about getting equality in volume/capacity then it is about how they look externally. Sort to speak, if I have 2 cases with in .002" in length of each other before fire-forming, I sure as hell want to have them blown near the same of each other after fire-forming as well.
Donovan

 

[fm1947]

Okay thanks guys, we're done in the fire forming part now back to load development, so far 2 nodes 31.4 varget and 32.2, the lighter one looked best at 200 yards 5 shots , measured center to center .348 and 32.2 was .61 I think I can do better with it.

 

[JEFFPPC]

Okay thanks guys, we're done in the fire forming part now back to load development, so far 2 nodes 31.4 varget and 32.2, the lighter one looked best at 200 yards 5 shots , measbout 200ured center to center .348 and 32.2 was .61 I think I can do better with it.

I have been shooting a pair of 6BRX's for 6 years. I shot around 1500 rds out of each every season. New barrels often. Your higher load is lighter than the lightest load I have ever used. I use Varget, 106EPS bullets, and BR4s. I am usually in the mid to upper 33 range. You might want a higher node, keeping a close eye on pressure signs.

 

[fm1947]

That 32.2 is 3050 fps, I understand there are two different reamers from DJ's Brass, he said one is .028 longer than the other, and holds more powder, I went as high as 34 grs varget and ruined some brass, way to high, anything over 32.3 is to high for mine, I talked to another guy that can't reach 33 either, glad you brought that up, been interested in what others are shooting.

 

[fm1947]

I have been shooting a pair of 6BRX's for 6 years. I shot around 1500 rds out of each every season. New barrels often. Your higher load is lighter than the lightest load I have ever used. I use Varget, 106EPS bullets, and BR4s. I am usually in the mid to upper 33 range. You might want a higher node, keeping a close eye on pressure signs.

Here's my reamer

 

[500Stroker]

I recommend that you do a very thorough inspection of that brass before you reload and fire it, if there is any strange marks running across the shoulder toward the neck throw them in the scrape bucket. I have had several split and it leaves a nasty scar on the surface the chamber. Lapua has had some issues that causes this condition on 6br brass. I also fire form with Varget - 30.0gr

 

[drumcorpschamp]

High end charges are often determined by feebore. Folks run from about .105" to over.200" and you'll see quite a difference in the top end accordingly.
And of course the disclaimer that "all guns are different".
Jerry

 

[dmoran]

@fm1947
That's a fairly short free-bore for long bullets.
Your needed load data will likely very a lot compared to others.
Just saying....
Donovan

 

[DJSBRS]

I suggest to measure those that your hitting a 2nd time very closely, in comparison. Any that do not blow out to within .004" of the others in length, I myself would cue out.

Good fire-forming to me is more about getting equality in volume/capacity then it is about how they look externally. Sort to speak, if I have 2 cases with in .002" in length of each other before fire-forming, I sure as hell want to have them blown near the same of each other after fire-forming as well.
Donovan[/QUOTE
Exactly! Proper Hydro-forming requires consistent same length as well.

DJ

DJ's Brass Service
205-461-4680

 

[fm1947]

Had some good results yesterday at the range 300 yards, headspace on case only varied .002 on fire forming, 32.1 varget at the lands produced a 6 shot 1 inch group measured from end to end , first two were out side made scope adjustment next 6 were great, also my bullseye camera sure helps seeing your shots in a mirage, and I have a few for sale on here. earlier in this thread I said it was running 3050, it's 3000 fps, really 5 shot avg was 3001, I did have it at 3050 was the high but it was to hot.