Thoughts on 6BR-AI reamer dimensions.

[Scarab]

My size die is sizing to .4695 at .200 line. Is this ok? The dam thing shoots at 31.5gr and I want to keep it there!!

 

[tclaunch]

My size die is sizing to .4695 at .200 line. Is this ok? The dam thing shoots at 31.5gr and I want to keep it there!!

It will shoot a cycle or 2 on the brass till it work hardens a bit, then bolt click at the top will be evident on every trigger pull.

My reamers are set up now at .4714" @ .200", to work with Redding sizing dies. The Redding measure .4695" as close as I can measure.

 

[Scarab]

It will shoot a cycle or 2 on the brass till it work hardens a bit, then bolt click at the top will be evident on every trigger pull.

My reamers are set up now at .4714" @ .200", to work with Redding sizing dies. The Redding measure .4695" as close as I can measure.

Ok, thank you for the info! I better call Harrels and get the right die!

 

[Alex Wheeler]

I have ran almost the same numbers in a dasher, .0005" at the base and .002" at the shoulder without issue. Currently Tom is getting those kind of numbers with his 6brai. We'd like to see a little more sizing at the base but no issues so far. So long as the die is truly sizing .0005" at the base you should be ok, but I'd probably go the next smaller die. My reamers are like Tim's .4715" at .2" they fit the dies better. Also I am sure you chamber is .4708" and the cases probably have not been hit enough to reflect that chamber size. I cant imagine any one specing a reamer that small. This is the kind of stuff that would cause clickers, not heavy bolt lift anyhow.

 

[tclaunch]

I`ll bet they suggest a D4, don`t know if they have a D5, they will shorten it for you to work with the BR-AI.

 

[Scarab]

They sent me a 3.0. Normally they want cases but said that is what everyone is using. The Harrels will be here today and I'll give it a try.
No clickers, just heavy bolt lift. Maybe it's to hot I sure hope not!

 

[tclaunch]

Heavy bolt lift all the way from the bottom would be pressure, hard opening of the bolt at the top, or called "clickers" is an improper sizing die. The 6BR-AI should be tuned with 105`s in the 2920 fps range according to someone I know who has more time with this round than anyone I know of, owner of Benchsource, David Dorris.

Some barrels hit pressure sooner than others, the difference between "fast" and "slow" barrels.

If you own a 0-1" blade mic you can measure the extraction groove before and after to see how hot your load is. There was someone here that his cases actually no longer would fit in his shell holder from trying to run Dasher speeds out of the smaller case.

 

[Scarab]

I'm at 2870 with the 31.5 Varget. On both my light and heavy gun. 28" barrels on both guns.

 

[tclaunch]

What actions?

 

[22DASHER]

I have to use the Harrells D4 die for my dasher chamber that is .4708 at the 200 line. D3 won't touch it.

 

[Scarab]

What actions?

Bat b light gun
Borden BRMXD drop port heavy gun

 

[Alex Wheeler]

When Harrell's cuts .080 off a D3 it tightens up almost .001" at the base and is like a D4 in a dasher. A D4 in a brai would be a very small die. Toms running his BRA at 2980-2990 with H4895 and heavy lift came around 3050 with a 28" 237 kreiger. They seem to take about 1-1.2 grains less powder than a dasher, but they dont give up any velocity. This case seems to handle a little more pressure than the dasher. One thing to check on Bordens is the ejector hole. It has a very sharp edge and will start to shave brass prematurely. A little 600 grit to dull the edge will help. Do the primers show pressure? What is the finish of the chamber?

 

[Scarab]

I don't think my Borden has an ejector, just an extracter since it's a drop port. I'll check that but I have contacted Jim about the thing shaving brass. He said something about honing the extracter and something about refusing to use a M16 extracter.
Chamber finish seems good, not polished or anything. No flat primers, it will flatten a match 205 primer, not a 450.

 

[X-Caveman]

I don't think my Borden has an ejector, just an extracter since it's a drop port. I'll check that but I have contacted Jim about the thing shaving brass. He said something about honing the extracter and something about refusing to use a M16 extracter.
Chamber finish seems good, not polished or anything. No flat primers, it will flatten a match 205 primer, not a 450.

My drop port BRXMD shaves a little brass, too. I'm 99% sure it's the extractor as there's a slight bump/ click when it hops over the rim when closing the bolt. In my case it's a straight 6BR. It's a bit annoying & unsettling on what's otherwise a very well timed & smooth action. I have not contacted Borden, but it piqued my interest when I read that you did. Did you get it resolved? My smith has offered to work on it, but so far I haven't sent him my bolt. I'm hoping it loosens up with use, but don't know that it will. I only have about 170 rounds on mine. How many do you have on yours and has it gotten any better with time? If not, I'll probably be mailing a bolt off for some tweaking soon. I just hate the risk of shipping if I don't have to do it. Thanks!

 

[DJ111]

Scarab,
Have you checked your overall length of your brass to your chamber? If you get over the chamber length you will get pressure.

 

[Scarab]

Scarab,
Have you checked your overall length of your brass to your chamber? If you get over the chamber length you will get pressure.

I'm .015 short. All brass is trimmed to same length.

 

[Scarab]

My drop port BRXMD shaves a little brass, too. I'm 99% sure it's the extractor as there's a slight bump/ click when it hops over the rim when closing the bolt. In my case it's a straight 6BR. It's a bit annoying & unsettling on what's otherwise a very well timed & smooth action. I have not contacted Borden, but it piqued my interest when I read that you did. Did you get it resolved? My smith has offered to work on it, but so far I haven't sent him my bolt. I'm hoping it loosens up with use, but don't know that it will. I only have about 170 rounds on mine. How many do you have on yours and has it gotten any better with time? If not, I'll probably be mailing a bolt off for some tweaking soon. I just hate the risk of shipping if I don't have to do it. Thanks!

470 rounds on mine and it's getting a little better. Borden will hone the ejecter for you if you give him a call.

 

[Alex Wheeler]

I don't think my Borden has an ejector, just an extracter since it's a drop port. I'll check that but I have contacted Jim about the thing shaving brass. He said something about honing the extracter and something about refusing to use a M16 extracter.
Chamber finish seems good, not polished or anything. No flat primers, it will flatten a match 205 primer, not a 450.

Your right, I missed the drop port part.

 

[Scarab]

Looks like my Brux Barrels are tight shooting Bart's 105's. Doesn't appear to be a die issue, it's a pressure issue. Thanks guys for the reamer/sizing die lessons!
Jeremy

 

[22DASHER]

For those of you that want to see a different reamer print, here is the one I went with: