6mm BR reamer JGS-1262
- Thread starter Jim Mc
- Start date
1-2 thousanths of taper in the neck is pretty standard for chambers. If that freebore will work for the bullets you plan on shooting, that reamer should be good.
I'd load up a couple of dummy rounds to make sure there is enough neck clearance with your lot(s) of brass too. Who knows what the new Lapua will be or if, for sure.
Mulligan
Silver $$ Contributor
Jim,
the FB diameter looks old school..... I went .2440 on my last dasher and might go a tad bigger if I had to do it again. With the current neck thickness of brass, I would think something closer to .274" might be a better no-turn chamber. Not sure I would swing with the tapered neck, but that is just me I reckon.
I attached a copy of my last dasher print, so you can compare.
Good luck
CW
edited to correct spelling error
the FB diameter looks old school..... I went .2440 on my last dasher and might go a tad bigger if I had to do it again. With the current neck thickness of brass, I would think something closer to .274" might be a better no-turn chamber. Not sure I would swing with the tapered neck, but that is just me I reckon.
I attached a copy of my last dasher print, so you can compare.
Good luck
CW
edited to correct spelling error
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Jim Mc
Silver $$ Contributor
Totally agree Clay, I would prefer the .2440. The .094 length would be fine but not so much the tapered neck.
that said, I'm often surprised on how well some of the standard spec reamers shoot.
Dolomite
Silver $$ Contributor
.272-.271 should work with no turned Lapua brass. Loaded round measures around .268-.269. Dirt or dust MIGHT cause issues.
6br Lapua brass measures around .0125 or so or .025 + .243 = .268. So you’ll have about .003 clearance roughly. If you can Measure brass wall thickness.
.271 neck won’t work for alpha brass which is slightly thicker.
.471 base is perfect to avoid clickers but it all depends which die you use.
.094 freebore can shoot 105’s or lower weight close to the lands and as the lands erode you can load longer or go heavier bullet. Depends how much powder you want to get in the case.
6br Lapua brass measures around .0125 or so or .025 + .243 = .268. So you’ll have about .003 clearance roughly. If you can Measure brass wall thickness.
.271 neck won’t work for alpha brass which is slightly thicker.
.471 base is perfect to avoid clickers but it all depends which die you use.
.094 freebore can shoot 105’s or lower weight close to the lands and as the lands erode you can load longer or go heavier bullet. Depends how much powder you want to get in the case.
Jim Mc
Silver $$ Contributor
great rundown, I was thinking just about like you have it listed, except the .271 neck and the Alpha brass not working well. Good catch on that one!
Mulligan
Silver $$ Contributor
Mulligan
Silver $$ Contributor
BR case neck thickness?
With my #'s Dave advised me to go with a .2725 neck. I don't shoot matches, just for my enjoyment and did not want to have to turn necks. Pointless for my needs.
forum.accurateshooter.com
Check out post #33
CW
edited to add pic,......... it took me a bit to figure out how to copy and paste this from post #33 on the attached link
CW
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Clancy
Silver $$ Contributor
That’s scary! I’ve got some brand new stuff that’s .268
I wonder how they let that batch of yours out? Could get someone hurt.
Do you have the lot number?
Mulligan
Silver $$ Contributor
Clancy
Silver $$ Contributor
Oh ok. Sometimes I think they report the high average on some of the lots. I have some of the PT02613 lot and it’s .2685 at the pressure ring. Not gonna argue with them over .0007 though, no doubt. Also, no telling how many pieces were in that lot and it could have drifted a little either way, of course.
Dolomite
Silver $$ Contributor
I wonder if that would work, almost like a false shoulder measuring half way down the neck. That could be a reason why the brass lasts so many firings. Just a thought.
DaveTooley
Gold $$ Contributor
This with a .274 nk
Jim Mc
Silver $$ Contributor
Thanks for posting this Clay, that's an eye opener. Now I've got to check what I have on hand. I don't mind turning necks for competition rifles but was looking for the easy button for a basic 6mmBR with an off the shelf reamer. I may bite the bullet and order a custom no turn reamer.
Jim Mc
newbieshooter
:-)
Ackman
Gold $$ Contributor
My 6BR reamer has .271 NK and 0 freebore. A 65Vmax seated touching, base of the boattail is above the beginning of neck/shoulder radius. A 58Vmax seats above that by whatever the difference in length is. I've also seen variations from lot to lot with these bullets, actually with very many commercial bullets. With each new box I check seating depth, but even within the same box there can easily be several thou. variation. And gold box Lapua brass is .269 loaded, Alpha 6BRAI is ,268 loaded.
Jim Mc
Silver $$ Contributor
I'm going to give them a try, just ordered two boxes of 50 from Graf's. I'll torture test a few pieces to see how long the primer pockets will hold up. Been wanting to do this for some time now and this is a good time to try them out.
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