6 BRA Extraction and bolt lift issues

[Webster]

Why not design brass that works with the popular chambers like Norma, lapua and Peterson?

Then your stuck with a reamer that forces you to only one brass option.

I though the chambers were made to SAAMI spec and the cartridges were made to fit a chamber of that spec.? When you buy a rifle they don't tell you what brand of brass you have to use?

 

[DaveTooley]

I though the chambers were made to SAAMI spec and the cartridges were made to fit a chamber of that spec.? When you buy a rifle they don't tell you what brand of brass you have to use?

The is no SAAMI spec for a BRA. Basic 6BR Norma yes.

 

[LRPV]

Thanks. Once it’s get here I’ll post some feedback on if I still have the heavier bolt lift at light loads along with new brass & fired brass measurement. I have a Micron 6 BRA sizer, but am planning on 1st thing firing 3 rounds 3Xs & send to Wiley at Whiddens for a custom sizer. If you have any advice it will be well taken & appreciated.
*If I had knew more before starting I would have definitely went with Lapua brass. If I think I’m sticking with the BRA I will get my gunsmith to help me get my numbers right to go with dummy rounds to send to JGS for a reamer. I tried to find C.I.P. to get their dimensions as I read that was what Alpha was basing thier reamer on. I found C.I.P., but not where they post info on cartridges.
Thanks & have a safe & blessed weekend!

I had to fire OCD Dasher brass 5x before the shoulder measurement would grow enough to chamber hard in my rifle. Might do some measurements and fitting along the way to make sure your brass is actually growing. I’m getting resistance on Dasher brass at the base but not in length. A sized case without shoulder bump allows a stripped bolt to fall without resistance. Just something to look at it before having a custom die made.

 

[mikecr]

Option 2 order a Reamer from Jim and spend 380.00 which should hit the shelves in 3 weeks.

I say stop having faith in anyone else, and make it right -yourself.
Measure your brass carefully, and fill out your reamer print.
Order the rough/finish or just finish reamer, and chamber your barrels.

After fully fire forming brass in your chamber, send some to a custom die maker, so that your die will work right.

 

[ChristianSilver]

I say stop having faith in anyone else, and make it right -yourself.
Measure your brass carefully, and fill out your reamer print.
Order the rough/finish or just finish reamer, and chamber your barrels.

After fully fire forming brass in your chamber, send some to a custom die maker, so that your die will work right.

I’m not going to go that route, time nor the patience.
I have chambered to many barrels that shoot .25 MOA groups at distance using Manson, JGS and PTG reamers. 284 Win, 6 Dasher, 6.5 PRC etc…

We don’t have to reinvent the wheel here with this mess. There are many, many barrels chambered using off the shelf reamers from the likes above that are shooting and winning. All I want is a properly chambered bbl, FB that meets the bullets to be used and one that accepts brass from the top tier manufactures.
If the Alpha brass won’t run then I’ll make changes to make it shoot. That may require trying the Alpha reamer, if not, Lapua brass. Barrels are expendables have 3 more 6mm blanks setting on the shelf.

 

[LVLAaron]

While the Alpha reamers are overpriced, they leave an incredible finish.

 

[Alex Wheeler]

I say stop having faith in anyone else, and make it right -yourself.
Measure your brass carefully, and fill out your reamer print.
Order the rough/finish or just finish reamer, and chamber your barrels.

After fully fire forming brass in your chamber, send some to a custom die maker, so that your die will work right.

Thats not how it works. I have worked out many chamber designs. How much clearence you need over virgin brass in the chamber, and how small the die has to be changes. There is no rule. You can not measure brass and design a chamber and reamer until you know that brass. Every brand will need a different chamber size and die size. You have to squeeze tough brass more than soft brass. That means the chamber has to be bigger too. If ADG is so tough it needs a smaller chamber you better hope you never get a clicker. Because you wont be able to make a sizer small enough to fix it.

 

[shoot4fun]

SO, Harrell's says send them three stick of brass fired three times in the rifle so they can match a FL die to your particular chamber/brass. I asked if they made the dies using those measurements and the answer was no. It turns out (and you al may know this) Harrell's has nothing to do with matching their dies other than having them cut to various sizes and they match your brass to the closest of those specs. Those dies are designated with numbers (EX #0, #1, etc). The tech I spoke to about matching Alpha BRA brass to a die said he had no idea about the .200 line numbers for each die and, more importantly, told me they did not like trying to match Alpha to any die they stocked. Completely honest information or just knowing I wasn't going to be happy no matter what die I used? Maybe just a case of didn't want to go into he details? Who knows. I do know that from the start (six firings) I have measured the .200 line using this item from PMA Tool

.200 Line Measuring Tool Kit

The highest quality, most innovative reloading tools and shooting supplies for precision riflemen. Unparalleled customer service. Shop Now - PMA Tool

www.pmatool.com

The results have yet to change. My .200 line measurement on Alpha 6BRA brass (even after 6 firings) is .4695 and that is well below the reamer number of .4714.
I am not experiencing hard bolt lift, ejector marks or any of the other nasty things associated with this brass.
BUT, there is something I've worked out and I am still in the experimental stages so I won't divulge anything as yet.

 

[JLT]

While the Alpha reamers are overpriced, they leave an incredible finish.

I believe they are carbide - that doesn't come cheap.

 

[LVLAaron]

Yeah, but 400 bucks is still steep for carbide... They leave the best finish I've ever seen, but are really picky on the speed they run, or they sing like a choir

 

[Lynn313]

I had to fire OCD Dasher brass 5x before the shoulder measurement would grow enough to chamber hard in my rifle. Might do some measurements and fitting along the way to make sure your brass is actually growing. I’m getting resistance on Dasher brass at the base but not in length. A sized case without shoulder bump allows a stripped bolt to fall without resistance. Just something to look at it before having a custom die made.

Thanks for the advice. I appreciate it and will check measurements good. It appears I made a good decision on going ahead and having the original chamber cut off. I hate losing an inch, but there was a ring formed somehow at .090” from the base of chamber. I posted pics in one of the threads. My gunsmith has a Alpha BRA reamer he used to recut.

I definitely won’t be looking for any more Black Friday deals on barrels. A very knowledgeable & kind machinist explained to me what he thinks happened to my firing pin & blown primer. With the Alpha case not expanding enough to seal when the firing pin struck the primer it drives the case forward with the explosion starting. Then without the case expanding enough to seal the case is blown back striking the firing pin again. My knowledge level is so much lower than his I might not have understood correctly. I still don’t understand how the ring at .090” was formed.