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338 BR

I wanted to get 2.7-2.8" OAL to use standard AICS magazines.

After playing with my current Robinette chamber, I'm not convinced I need any extra length. Touch point with the 215 Hybrid is 2.435. That length fits perfectly in my MDT mag. I rarely load the mag. Most times I insert a single shot sled, but I do want the option of follow up shots.
With that said, here's a couple of images.

215 Hybrid at touch. View attachment 1594584

215 projectile next to dummy cartridge.

View attachment 1594585

There's more than enough room for 10-ish grains of powder for subsonic use.

If, for some reason I want to shoot the 125 NBT supersonic, I can get 34gr of LT 30 underneath it. Probably a lot more if I go a ball powder.


Dangit, now I'll have to build the 30 first, then maybe the 338 down the road.
No doubt about it, that's a great looking round! I need to stop following this thread as it is gonna cost me!
Paul
 
No doubt about it, that's a great looking round! I need to stop following this thread as it is gonna cost me!
Paul

Just remember, you can get the 125 NBT to 2900 with a 22" barrel.
That's pretty good, low recoil medicine on deer sized game.
I have no idea how it'll shoot in the 8tw. Probably just fine at 2800 and spinning like crazy.
Should knock down pigs okay.

I'm still gonna shoot the first one subsonic though.

Ignore the ugly brass above. It's really, really old Remington 6-BR brass that just got a neck sizing to hold the bullet. It kind of scraped its way into my dirty chamber.
 
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I have a 1-7 twist barrel. Have shot deer with the 200 SST going around 2200 fps. Did a good job of bring it down. Shoot the 300 gr sub sonic for fun at steel. No problem hearing the ring. Use 7 BR brass and my dies are from CH4D.
 
For a hunting bullet try these. They are very accurate in a BO bolt gun I have. Not sure but you might be able to use these in both sub and moderate supersonic loads.

Edit; Just watched their video and you can't shoot this much past 1100 FPS


I've heard a lot of good things about those. Probably should have stopped by Bass Pro on the way home to see if they had any.
I'll grab some if I see any on the shelf. If not, I'll order some.
 
I have a 1-7 twist barrel. Have shot deer with the 200 SST going around 2200 fps. Did a good job of bring it down. Shoot the 300 gr sub sonic for fun at steel. No problem hearing the ring. Use 7 BR brass and my dies are from CH4D.

Every time I watch this video, it makes me want sub stuff even more.

 
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For a subsonic round, how much does the case matter? We're all aiming for 1050 with a 300 grain bullet.


I guess there are probably stick powders that will work in the BR sized case?
 
For a subsonic round, how much does the case matter? We're all aiming for 1050 with a 300 grain bullet.


I guess there are probably stick powders that will work in the BR sized case?

I would say, probably doesn't matter a whole lot.
The fireball case would work. (JDJ)
The 10mm or 224 Valkyrie works. (Spectre)
A shortened CM case (GT sized) works. (8.6 BO)
The 7.62x39/PPC/ARC works.(Not sure of the names)
The 308 case works.

For me, it's just a personal preference because it works as a sub cartridge and hits targeted supersonic velocity with the 125 class 308 bullets.

I don't want to use brass that pretty much forces me to use no longer available powders like Trail Boss.
Being able to use pistol powders and most likely even the burn rate of AA-1680 or a bit slower, seems logical in my pea brain.




Doing it in 338, could/would work with the 180/200 bullets for supersonic stuff, but there's still the issue of gunsmith and projectile cost.
Then a new supressor...
I have to choose wisely with my retired pay.




I do want the 338-BR, but the 8tw sub 30-BR makes waaaay more sense right now.
 
I just ordered a couple hundred berger 230's. I'm moving to a new place soon and will be able to shoot on my property, so I want some fun gun to shoot :)
 
Keep us posted. I have a 30BR I want to throat out. It’s a 10 twist though.

Pop the numbers into your calculator.
There is a huge elevation difference at 500yds from the 8tw to the 10tw.
I thought it was wrong so I tried other calculators and got pretty much the same thing



8 twist.

Screenshot_20240930_192911.jpg




10 twist.

Screenshot_20241002_131814.jpg


Edited.
I posted the wrong image above. Removed and replaced it to represent 10tw at 500 yards, not 8tw at 700
 
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Lol, my smith just sent me a pic of a 338br reamer he forgot he had and asked if I wanted to build one. I told him the money I'd save on powder would be spent on bullets!
 
I have a reamer I bought years ago from ptg throated for 300gr SMk. It was part of a sale. An other forum ,a member on quarterbore.com had bought the other one throated for the 250’s.
now that my local barrel maker can make 7 and 8 twist barrels I might have use for it.
sorry I m not in the same country otherwise I would have helped you.
 

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