6br primer

[Mudder]

Question....
Have you ever had a 6br that would only shoot with a cci450???

I wonder if I'm seeing that in one of mine or if I'm missing something else.
Cheers

 

[jr600yd]

Mine shoots Remington 7 1/2's, 450's BR4's all about the same. Only have to make slight sight adjustments for each.

 

[OIF/OEF]

Mine prefers Remington 7 1/2 and Tula's. The tula's shoot great and I switched to them when the Rem 7 1/2 were very difficult to find in these parts. I did try the BR4 and noticed the groups opened up. I didn't do load testing to try and improve groups with the BR4 ill be honest.


Very Respectfully

 

[gambleone]

Have you tried wolf primers?

 

[Mudder]

450s seem to help quite a bit today. I've also been working with imr4166 so I think that is part of it. In two rifles it seems to need about 1 grain less than varget, and I ended up with 29.3 grains of 4166, cci450, and Berger 105htg vld at .01 in the lands.

I do have some wolfs but haven't tried them yet.

 

[CaptainMal]

Agree with your assessment of about 1 grain less than Varget. I did the same with a 6 Dasher I recently sold. 450's also were the primer.

One thing I could not figure out was the small ES with the 4166 did NOT translate to the smallest groups, no matter how hard I fiddled with it.

Went back to Varget with my new Dasher rifle. Took .7 of a grain more than the 4177, higher ES but better accuracy.

Beats me.

 

[Laurie]

Went back to Varget with my new Dasher rifle. Took .7 of a grain more than the 4177, higher ES but better accuracy.

That's the barrel harmonics issue. The pressure / velocity combination that gives the best precision might not coincide with the load that produces the smallest ES, but the barrel / action / bedding combination effectively 'ignores' (ie behaves identically for) pressure / velocity variations around the 'node'. (That's what OCR type load testing looks for.)

Unless you're lucky and get those two happy states to coincide with a particular loading, the only way of getting them reconciled is by using a barrel tuner - find the load that provides the tiny MV spread and then 'tune the barrel' (change its harmonics) to give small groups with it. That's the theory anyway and it seems to work for some, but barrel tuners have yet to catch on really widely.

 

[Mudder]

Agree with your assessment of about 1 grain less than Varget. I did the same with a 6 Dasher I recently sold. 450's also were the primer.

One thing I could not figure out was the small ES with the 4166 did NOT translate to the smallest groups, no matter how hard I fiddled with it.

Went back to Varget with my new Dasher rifle. Took .7 of a grain more than the 4177, higher ES but better accuracy.

Beats me.

I'm totally out of Varget and was not having luck with imr4895, so I'm working with it in two BRs and two Dashers. All are in that one grain less area. I've had some excellent groups with it but it took me a couple weeks to find the sweet spots.

I'm thinking a 4166 thread would be helpful.....

 

[CaptainMal]

May try some slower 4451. Concern is the size of the granules compared to H4350. You need a long drop tube and care to get enough in the case. IMR 4350 granules are too big to get enough in for velocity. 4451 might or might not be an option.

Varget is so dirty and build pressure fast that something slower might be lower pressure and give longer case and barrel life while being cleaner.

 

[Judd]

I've noticed a barrel to prefer a certain primer over others. Not necessarily won't shoot the others but it will shoot something best...whether that be groups or SD #'s. My br/brx's have liked 450's and my dasher barrels have liked Federals...kinda weird to me but up to this point it's been consistently that way.