BRA die question.

[MDM]

So I've got a couple of BRA's up and running. Accuracy is phenomenal. I'm using Forster FL Dasher dies that I trimmed. The problem I'm having is it just feels like the dies are just sizing too much on the body and shoulder junction. The brass at the shoulder measures what it should after firing according to the print, .460-.4605. The die sized the shoulder down. to .457 and down .001 at the .200 line. It just feels excessive when running thru the press compared to what I'm used to with 6.5 and 6 x47.

I'm getting to a question, so hang with me. I just sent a few fired cases to Harrels to get a proper fit so this should be remedied soon. I'm running a couple of different barrels at 28" and I'm just not getting the speed that seems to be the norm here with 4895 and Varget. I know, lots of variables there, but 2905 with a 28" bartlien (30.4 4895, any more and I'm seeing more pressure than I'd like with no way to get to the next node). A Muller that only has 70 on it, but it right at 2875 with the same load and its about top end for pressure. Accuracy is awesome, just cant get close to 2950 without pressure. Now, my question... could excessive sizing of the case lead to more thrust on the bolt face during firing? IE. the body is not gripping the chamber like a properly sized case would. FYI, I hit all my chambers with a quick 400 to get some cross hash and grip, as the theory goes. Thoughts?

 

[dkhunt14]

I would think that it isn't the cause. I believe once pressure starts, it happens so fast. You may be losing a little case capacity, but i don't believe that is the cause. I would tend to believe a fast lot of powder or slow tight barrels. Maybe not enough freebore. Matt

 

[Gilbert Garza]

I’m kinda having the same issue, I trimmed Wilson dies and got about the same measurements as you. I don’t have visible pressure signs but bolt lift is a tad firmer then my Dasher ever was.

Following hoping for ideas

 

[MDM]

.104 fb, .272 neck, loaded .269, shooting 105H

barrel #1 is .237 (Takes a .2372 bushing) 5r 7.5 twist

barrel #2 is a .236 (Takes a .2364 bushing) 4 groove, 7 twist

I was expecting less speed/more pressure out of the Muller because its a .236/7 vs the Bartlien .237/7.5 Don't get me wrong, with the way they are shooting, I'm more than happy with running them where they are, just wondering why I'm not seeing the speed the majority are seeing thru 2 barrels now. I've got two different lots of 4895 and Varget. No difference in speed worth noting, about 10 fps between them with the same charges.

 

[X-Caveman]

What bullet(s)? Never mind. I've never shot a 105 hybrid. I've found Berger 108s and BIB104s won't go as fast as 105 VLDs, VT103s, Bart's 105 Infinities.

 

[steve123]

Probably the faster twists rob a little velocity compared to an 8 twist???

 

[gunsandgunsmithing]

I don't think it's your velocity issue but I agree that your die is sizing excessively compared to your chamber/fired brass. I like about half of that...about .0015 @shoulder/body junction and about .0005-.0006"@ the .200 line.

As for the bolt thrust...I doubt it seriously. Now, if you bump the shoulders excessively, different story, IMHO.

 

[MDM]

I figured it was a reach.

7.5 twist is about the minimum I can go without compromising bc for the temp ranges I can shoot in throughout the year. I'll report back if the new dies should change anything, but I'm not counting on it.

 

[tmwinds]

Have you compared your chronograph with others? Also, H-4895 is hit or miss depending on which lot you get. I ruined the primer pocked on 100 rounds of brass with 30.6 grains. Since I only shoot 600 yards max I went with a moderate load of Varget and the gun is happy.

 

[MDM]

Yeah, chrony is a magneto v3. Mv is correct and confirmed thru 3 matches and out to 1300 yds.

 

[ckaberna]

Chase accuracy... not speed. If they come together great.
What is a few more clicks up?

 

[Sheldon N]

My Forster dies are giving me sizing to .458 at the shoulder/body junction, with fired brass at .460 - .4605. I'm at 5-6 firings on the brass and haven't noticed any issue with pressure. I've had it up in the high 2900's just shy of 3000 fps, but it seems happier for me down lower. I'm at 2923fps with a 105, 30.7gr H4895, 26" Hawk Hill.

 

[RDA72927]

So I've got a couple of BRA's up and running. Accuracy is phenomenal. I'm using Forster FL Dasher dies that I trimmed. The problem I'm having is it just feels like the dies are just sizing too much on the body and shoulder junction. The brass at the shoulder measures what it should after firing according to the print, .460-.4605. The die sized the shoulder down. to .457 and down .001 at the .200 line.

The plan of using a Dasher die cut down is what a buddy and I are going to do, but we are going to have the 6 BRA reamer changed to the spec's of Dasher resizing die cut down to avoid that issue..

 

[Gilbert Garza]

My Forster dies are giving me sizing to .458 at the shoulder/body junction, with fired brass at .460 - .4605. I'm at 5-6 firings on the brass and haven't noticed any issue with pressure.

Do you know your base measurements at .200” fired & sized ? Those shoulder #’s are same as my Wilson dies

 

[MDM]

Just got my Harrells in. #2 dies is what they sent. WAY better. Any particular brand of bushing you guys like to use with the Harrells?

 

[BRGUY]

I use Redding for all my neck die bushings.

 

[LRPV]

Just got my Harrells in. #2 dies is what they sent. WAY better. Any particular brand of bushing you guys like to use with the Harrells?

Custom Reloading Tools. Unfortunately, I think Whidden is the only place you can buy them now.

 

[Gilbert Garza]

Just got my Harrells in. #2 dies is what they sent. WAY better.

Mind sharing after sized measurements at the shoulder and .200”

Thank you

 

[10at6]

So I've got a couple of BRA's up and running. Accuracy is phenomenal. I'm using Forster FL Dasher dies that I trimmed. The problem I'm having is it just feels like the dies are just sizing too much on the body and shoulder junction. The brass at the shoulder measures what it should after firing according to the print, .460-.4605. The die sized the shoulder down. to .457 and down .001 at the .200 line. It just feels excessive when running thru the press compared to what I'm used to with 6.5 and 6 x47.

I'm getting to a question, so hang with me. I just sent a few fired cases to Harrels to get a proper fit so this should be remedied soon. I'm running a couple of different barrels at 28" and I'm just not getting the speed that seems to be the norm here with 4895 and Varget. I know, lots of variables there, but 2905 with a 28" bartlien (30.4 4895, any more and I'm seeing more pressure than I'd like with no way to get to the next node). A Muller that only has 70 on it, but it right at 2875 with the same load and its about top end for pressure. Accuracy is awesome, just cant get close to 2950 without pressure. Now, my question... could excessive sizing of the case lead to more thrust on the bolt face during firing? IE. the body is not gripping the chamber like a properly sized case would. FYI, I hit all my chambers with a quick 400 to get some cross hash and grip, as the theory goes. Thoughts?

Same here... you need the D3 6 dasher sizing dies from Harrels....I had mine trimmed 90 thou and it it is perfect. But the trimmed Forstner seater works great
You best talk to your gunsmith about the reamer he used
2950 here with both 30.6 of h4895 or 31.5 of re15

 

[Sheldon N]

Do you know your base measurements at .200” fired & sized ? Those shoulder #’s are same as my Wilson dies

Running brass that's at about 6 firings I get 0.0006 to 0.0007 at the .200 line. Fired brass is .4715 and sized brass comes out at .4708 to .4709 with my Forster dies. What base sizing are you getting with your Wilson dies?