6BRX pressure signs at 30.5 Varget

[fa18hooker]

Shooters,
Need some help here...just built a 6BRX with a 1:8 Kreiger barrel (forgot the land diameter, but it was the tighter of the two offered). I'm using Norma brass and Federal 205M primers. Loaded with 30.5 of Varget for fireforming (with the bullet in the lands), I'm getting blown/pierced primers and ejector shine spots. After fireforming, I loaded 30.5 of Varget and got 2800 fps, but the same pressure signs. I'm reading posts with guys loading 33 grains of Varget...I'm scared to even load 31. Anyone else have these issues? My thought is it might be the tighter barrel, can't think of anything else. Any help is appreciated.

Thanks,
Matt

 

[cmillard]

that would probably be a .236 bore. you might see some signs since it is new unfired brass--have you tried lapua brass? what bullets are you using? in some of my testing of other calibers, the fed 205s were hotter than others. i dont use the fed 205s anymore--just wolf srm and cci br-4s.

 

[DukeDuke]

I'd try different powder. My fireforming load was 105 a-max with 30.0 gr of RL-15 at 2900 fps, no pressure, lapua brass.

 

[MarkS]

fa18hooker,

My fireforming load is 29.5gr Varget with a 105gr bullet. 30.5 gr would be a little hot for fireforming. 30.5 is a max working load in one of my BR's. I think you are too hot for fireforming.

Have you tried the same load in a FF case? Do you have the same problem?

You did not say what action you used. The large firing pin hole of a Remington can cause pierced and heavy cratering of primers, with hotter loads. CCI primers should help. Having the firing pin hole bushing would fit this problem.




33gr of Varget is the range for A 6BRX, but all guns are different. I changed to the 108 berger and had to back off to 32.7gr. When the 105gr VLD shot with 33.3gr

All my 8tw are the 0.236" bore. I don't think that is the problem.

Back off to 29.0 gr for FF and go up from there. If you still have the problem with fired cases, you need to have the gunsmith look at it.

Mark Schronce

 

[DJ111]

Try fire forming with 29.5-30.0 grains of Varget and shoot that load again on the second firing also to make sure the case is formed all of the way as mine would be a few thousanths short in the shoulder. I shot around 32.5-32.8 grains of Varget in mine with a .236 bore on a Savage taget action.

You may want to try some CCI 450 primers as they have a harder cup than the 205's and may prevent the piercing.

Dallas

 

[Bob3700]

When my brother and I first started shooting the BRX, the first thing we had done was bushing the firing pins on our Remington actions down to .062. Good idea.

We found that the Fed 205 primers were prone to showing pressure and switched to Wolf Small Rifle Mag, Rem 7 1/2 and CCI 450s. All of those will let you get up to the levels the BRX is capable of shooting at.

We are slightly above 33 gr of Varget and RL 15 with Moly'ed 105-107 gr bullets and getting just over 3000 fps from 30 inch tubes.

HTH

Bob

 

[fa18hooker]

Thanks for all the input. Forgot to include that yes, it's a Remington 700 (so I guess I'm sending off the bolt to get the firing pin bushed...any suggestions on who to send it to?) and I'm shooting Sierra 107s. I've since tried the CCI BR4's with 30.5 of Varget in fireformed brass, and I get a shiny spot where the ejector is...so that may be the Norma vs. Lapua brass. Appreciate the collective knowledge...

 

[DJ111]

Send the bolt to Gre-Tan Rifles.

http://www.gretanrifles.com/

Very fast turn around time.

Good Luck,
Dallas

 

[fa18hooker]

Thanks Lynn...anyone out there want to trade some Norma 6BR brass for Lapua?

 

[nfa1eab]

Matt,
I too showed ejector marks on Lapua brass in a Rem. 700 with the small bushed firing pin but no primer issues with 7 1/2s, Wolf SRMs, and CCI 450s. I fireform with 30.5 gr. of Varget and 107 Sierra's and get goods results using the false shoulder method. The ejector marks showed until I removed the ejector plunger and epoxied in a piece of drill rod to fill the hole. I have been shooting 33.6 gr. Rel 15 with 105 Bergers (Moly'd) @ 3,035 FPS and 33.5 gr. of N140 with 107 Sierras (Moly'd) @ 3,025 fps without abnormal pressure. 10 firings on the cases, no loose pockets, no piercings, excessive flattening, or cratering, and no bolt lift clicks. Both loads hammer at 600. If they go out of the X-ring, I pointed it there, or missed a change. Have shot 33.2 gr. Varget @ 3,000 fps with these bullets and no pressure signs (not as accurate as the others). Barrel is a PacNor 1-8 twist .236" land, 30.25", .104" freebore.
Don't misunderstand, these are top end loads, so work up accordingly. I am just saying they don't hurt the brass, which is how I judge the pressure. These bullets seem to like 3,000 - 3,050 fps and are accurate at these speeds, which after all, is the only reason to shoot the BRX rather a standard BR.