Welcome to the .375 350gr SMK

[MIKEONE]

Well I finally got some bullets for my .375 build. I could not get any info or pictures and that pissed me off so here are some pics, 1.75 in long so a 10 twist should be fine.



These should be interesting with a .40 cal pistol can.



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Mike

[Spook]

Nice! What are you launching them with?

[strycnine]

Originally Posted by MIKEONE

Well I finally got some bullets for my .375 build. I could not get any info or pictures and that pissed me off so here are some pics, 1.75 in long so a 10 twist should be fine.



These should be interesting with a .40 cal pistol can.



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Mike

That's a serious chuck of copper and lead! What you going to shoot them out of?

[MIKEONE]

Lets just say for now, something that requires a few stamps and some custom reamers to arrive so I can make dies and chamber the barrel.

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[Artful]

Originally Posted by MIKEONE

Lets just say for now, something that requires a few stamps and some custom reamers to arrive so I can make dies and chamber the barrel.

Tease - I saw a 375 WCF contender barrel with a 1:12 twist and thought about making one up. I have a NEI mold that you put 3/8 copper tubing in and cast a jacketed bullet - it would be a sweet cheap toy.

[LouBoyd]

That must be a new bullet from Sierra. It's not in my Quckload database. Could you post it's important dimensions for handloading? Those would be:
Overal length
shank length
boattail length
boatail diameter.
Has Sierra stated it's G1 BC? I'd expect it to be close to the 300 grain 338 SMK. It would deliver 16% more energy at the same velocity just because of the added mass.

I haven't seen this bullet before but I've looked at what could shoot the 375 330 grain Lehghs subsonic and concluded that they would work nicely in a bolt action using a cartridge like a 7mm BR but with a .375 neck. It would probably be easiest to make by necking down 308 brass, The shoulder would only be .06" larger than the neck, but that's plenty. I'd expect that to be good for the 350 SMK too.

Dies would only requre reaming the neck area of a 7mmBR die to .400 +/- and using a 375 expander ball.

A custom chamber reamer might be requried but I thnk it could be chambered using a 7mm BR reamer with an overside pilot (or a solid pilot in a well aligned lathe) to cut the shouilder followed by a 375 Win Reamer to cut the throat and neck.

The 375 WIn cartridge has 48 grains capacity compared to about 41 for a 378-7mmBR and about the same pressure rating. The smaller capacity should give a little better velocity consistancy. The other advantage of the 7mm BR is it's shorter and uses a 308 size boltface. To me it sounds like a good use for a 30-06 or 270 mid length Win 70 or similar requiring no modifications other than a barrel change. I'm not sure with the Sierra 350 SMK but I don't think 375-7mmBR with the 330 grain Lehighs will fit in a 2.8" or even a 3.0" short action.

[pud-knocker]

Originally Posted by LouBoyd

.....That must be a new bullet from Sierra. It's not in my Quckload database......

I heard that Cheytac had a special run of them made for their 375 chey, jamison is making the brass, 160gr H20 capacity, lots of BOOM.....something close to a buck a piece for the .375 / 350gr......

here are a few thread links.....

https://www.24hourcampfire.com/ubbth...2442390/page/1


http://www.snipershide.com/forum/ubb...Number=1400575

http://www.jamisoninternational.com/...ytac/288874203

[MIKEONE]

I did a workup in Quickdesign, and got a projectile that is close in most regards, without going to a coordinate plotting machine. Ill post it when I find what computer it's on.

im gonna do a ar-10 and a bolt so when the parts and stamps arrive it's on.

Should be fun.

Mike

[MIKEONE]

This is the first attempt, The ogive radius may be a tad off lol and the bearing surface!! I cant seem to find the 2nd one I did but here's something



Mike

[Spook]

Mike is this gonna be a a 375 off a 6BR case?