6MM BR Load Question

[ehkempf]

I have three 6MM BR rifles. One is a 40X with 22” barrel 1-14 twist the other two are a 40X and Rem. 700 both with 26” barrels and 1-12 twist. All three seem to shoot very well with 68-70 g bullets using H4895 with loads between 30.7 to 31.1 g. This load does not fill the case. From the group of benchrest shooters that I shoot with, they all shoot either 6 PPC or 30BR; they all say that the case needs to be nearly filled for best results. I know I cannot do this using H4895. So my question is there a better powder selection that I should be trying. I am interested in only short range (100, 200 yard) VFS type shooting. Why the need for a nearly filled case?

Thanks,

Ed

 

[dansig]

33.5gr N-135 will go just a bit up the neck, with a long drop tube it still coveres the sholders.

Been shooting this load for a year, average group is about .15" with as low as .065"

Got 13.5 twist barrel and shooting 68gr Bergers

 

[hogpatrol]

With Norma brass, 31.9 grains VV135 comes up to about 1/8 inch down from the top of the neck. Lapua, somewhat lower. I have two 1-14s and VV135 and 66s & 68s work best for them.

 

[AndyTaber]

There are a couple of us shooting 100-200 Benchrest at our club with the 6mmBr 14 twist and having very good success with 33 gr of Varget. Fills the case to the shoulder. I had contemplated using vv135 when one of the long time benchrest shooters said, "If Varget is working, why go a more expensive harder to get powder?" I have also used the same powder charge with a 70 gr SMK at 600 yards and saw no reason to try anything else.

 

[dansig]

if your group average is below .1" then no reason to change powders or anything else... if you are shooting .2" groups or larger then you might consider changing something...

N-135 is very stable and consistent, I've shot .065" groups with a rebarreled Howa 1500 and 33.5gn N-135

 

[madmixerman]

Another vote for N135 . My load is the same. 33.5 gr N135 ,68 Bergers 14 twist Kreiger on a Viper action. Very accurate & consistant.

 

[ehkempf]

Thanks for all the replys. I will try N135, the problem is finding it in our area. Would like to buy in 1lb jug just to try, before commiting to 8 lb jug. I know it is a good powder, but it is had to find.

Thanks,

Ed

 

[LHSmith]

dansig- The OP is talking BR competition, VFS specifically, which requires 25 shots for record through 5 matches occuring throughout the day........if one has a rifle that averages below 0.100 inches, he'd best put that puppy away, and save that barrel for either the FISS (group) or the Score Nationals (IBS).
Agging a 0.200 in many IBS tournaments will likely get you some wood.
We are talking 6 BR which up to this point in time does not agg as small as as the PPC. If the OP takes your advice, he'll burn his barrel out trying to obtain the unattainable.
The advice to choose a powder that fills the case is good......there are many theories why.......I just know that this advice is golden as it has served me well.

 

[GSPV]

I'm not being a smart aleck. Take this FWIW.

As long as the 100-200 VFS is the game, I think that your best answer is going 33.0-33.5 gr of 4198, after swapping to 30 BR. That big hole is hard to overcome in the X count.

 

[Lapua40X]

I too have heard a lot about filling the case and I suppose, theoretically, it makes sense to some degree. But in my experience with the 6BR I shoot (Remington 40X 6BR Norma 1 in 8 twist) the amount of powder in the case is of lesser significance than the type and amount of powder, bullet and OAL. My rifle shoots 107 gr. Sierras with 30.5 - 31.0 grains of Varget (powder load depending on whether it's winter or summer) along virtually the same straight string.
I don't believe any one load works best in all rifles, even rifles with identical twist, barrel length, etc.. I've seen rifles that might be considered identical where one seemed to prefer Bergers and the other Sierras. One worked better with a .015 jump the other with the bullet locked into the lands. Bullets of the same weight but from different manufacturers will often function better with a faster or slower twist, depending on the barrel/bullet match up. Also, powder can vary from one lot to another and I have found it necessary to make adjustments between one lot of powder and another purchased at the same time.
Point - When your groups open up and the guy at the next bench suggests you may not have your cases full enough, file the information away and, if you think the idea has merit, beg borrow or steal a few grains of a slower burning powder and experiment. But don't expect it to work miracles. There's a lot more to fine tuning the 6BR than filling up the cases.

 

[fdshuster]

I had a 14 twist 6BR built with a Bartlein heavy straight contour barrel, 24", chamber cut with my .269" neck dia. reamer, glass pillar bedded, etc. Never could get it to shoot consistantly using the same loads that work great in my other 14 twist 6BR's.

Just tried the load suggested by madmixerman: 33.5 grs. of N135, 68 gr. Berger #24411 seated to touch, 205 primers, and the rifle has come alive. Previous velocities with other loads were averaging 3320 fps, and the new load is 3557. SD and ES numbers are higher than with the other loads, but 5 and 10 shot groups have all been excellent, proving to me that "good" SD & ES numbers do not always produce the smallest groups.

This is now the standard load for this rifle, and with the beginning of the match's next Spring, it will be used. Until now I could never depend on it to produce competitive scores.

Also proving again, all rifles are different.