300 bo
- Thread starter Mainiac
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Hmm, does 145gr PB @ 2150 fps from AR (1:10), almost MOA @ 100 count? I would say easy MOA but the gas port probably dinged the base so I got an almost circular array on the target. Target of 1:8 CVA SS, finding drop at 100. Quicky test, as you see Gold Dot dropped about the same. Some are trying cast in 300 Hamr, no real results yet. You can get 1:10 barrels, mine is McGowan.
CWLONGSHOT
Well-Known Member
I have a 250 grain load that shoots very well subsonic. I haven't found anything else that's really stellar accuracy wise at least when you compare it to jacket loads.
I haven't got cast in my HAM'r yet. I got it knowing it wasn't going to be a cast bullet caliber.
If I was going to buy a 300 blackout specifically for cast, I would buy something that offered it in a one and 10 twist @ longer than 16".
CW
I haven't got cast in my HAM'r yet. I got it knowing it wasn't going to be a cast bullet caliber.
If I was going to buy a 300 blackout specifically for cast, I would buy something that offered it in a one and 10 twist @ longer than 16".
CW
Im thinking 300hamr would shoot cast awesome,with that slow twist,,,thats why im intrested in it.
fiver
Well-Known Member
my AAC shoots the rcbs 165gr silhouette bullet on top of #-9 to about 15-1600 fps pretty darn good.
unfortunately that combination wouldn't chamber in the one 300 AR i got a chance to work with.
you wouldn't think a 7 twist capable of that, but i tend to ignore stuff like that and just see what the gun will give me.
anyway don't be overly surprised if half of the cast bullet and load recommendations you get won't chamber in your rifle, or make it function even if it does.
unfortunately that combination wouldn't chamber in the one 300 AR i got a chance to work with.
you wouldn't think a 7 twist capable of that, but i tend to ignore stuff like that and just see what the gun will give me.
anyway don't be overly surprised if half of the cast bullet and load recommendations you get won't chamber in your rifle, or make it function even if it does.
CWLONGSHOT
Well-Known Member
Before I bought mine when I was researching I had a back and forth with Wilson and he told me he didn't design it with cast in mind and frankly the chamber dims where kept very tight and cast likely would not work well.
I havent tried any in mine yet.
CW
These feed and function in Wilson 15-twist 300 Ham'r:
RCBS 7.62-130-SPL
ACC 31-142-FN
NOE 309-146-SP
NOE 311-152-SP
All were GC'd and PC'd (Smoke's clear).
I have no notes on accuracy, although they all hit paper. These were for F&F testing last year. I need to get back on this project.
As mentioned above, chamber and throat is tight, and that presents a problem in cast bullet selection. Throats in 300 BO can be similarly short, too.
Cast bullet load data is severely lacking. Get that last round from the mag to fully lock BCG back and then start running them across a chrono and mark where the brass piles up during load development. IIRC case capacity of the 300 Ham'r is about 95% of 7.62x39 - but don't hold me to that number. That is how I began to develop some cast load data that worked. DO NOT take that 95% number as gospel - test for yourself. There is a fair bit of 7.62x39 cast data available to work from.
Also if IIRC the 300 Ham'r case body is slightly blown out, so use fired cases to test usable powder space. I bought cases, because I wanted them properly head stamped. I made my own 7.62-40WT cases from LC 5.56, and they work just fine, too.
Personally, I like the 300 Ham'r. The 7.62x40WT (12-twist) is not bad either. Both of these were designed to be supersonic from the gitgo.
Just in case you may wonder why I have both, I had the 7.62x40 long before the 300 Ham'r. Then I hit a really good sale on a 300 Ham'r barrel, and the rest as they say is history.
RCBS 7.62-130-SPL
ACC 31-142-FN
NOE 309-146-SP
NOE 311-152-SP
All were GC'd and PC'd (Smoke's clear).
I have no notes on accuracy, although they all hit paper. These were for F&F testing last year. I need to get back on this project.
As mentioned above, chamber and throat is tight, and that presents a problem in cast bullet selection. Throats in 300 BO can be similarly short, too.
Cast bullet load data is severely lacking. Get that last round from the mag to fully lock BCG back and then start running them across a chrono and mark where the brass piles up during load development. IIRC case capacity of the 300 Ham'r is about 95% of 7.62x39 - but don't hold me to that number. That is how I began to develop some cast load data that worked. DO NOT take that 95% number as gospel - test for yourself. There is a fair bit of 7.62x39 cast data available to work from.
Also if IIRC the 300 Ham'r case body is slightly blown out, so use fired cases to test usable powder space. I bought cases, because I wanted them properly head stamped. I made my own 7.62-40WT cases from LC 5.56, and they work just fine, too.
Personally, I like the 300 Ham'r. The 7.62x40WT (12-twist) is not bad either. Both of these were designed to be supersonic from the gitgo.
Just in case you may wonder why I have both, I had the 7.62x40 long before the 300 Ham'r. Then I hit a really good sale on a 300 Ham'r barrel, and the rest as they say is history.
CWLONGSHOT
Well-Known Member
I was just thinking, Zinc cast bullets might be a good proposition in the HAM'r.
CW
CW
CWLONGSHOT
Well-Known Member
Its not a long range caliber. How much of a detriment would it be for inside 200yards on paper n steel??
I bet they wouldn’t do too great at 200. The lack of weight would cause them to shed velocity pretty quick. Which can you throw more accurately at 50 yards- a baseball of a nerf ball?
In a rifle maybe 50 yards? I wouldn’t expect much beyond 100.
In a rifle maybe 50 yards? I wouldn’t expect much beyond 100.
CWLONGSHOT
Well-Known Member
We are still talking with in normal lighter weight range of the Cartritage. Say 120-140g. I have shot a S. ton of 110g cupncore to 200y no issue. A longer projectile in this twist rate may be the difference.
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Bingo! It is, sometimes, about the BC of a bullet. And mass is part of that calculation. Reduce the mass, for the same total shape, by 40% and what happens to the BC?
They will get to 200 yards, it will just take them longer. They will shed velocity faster. Wind affects them more as it has longer to work on them. Physics matters.
However, if anyone here is gonna try it and see what happens it will be you. That isn’t a dig, it is a compliment. Would be an interesting comparison to see. Same mould, same load, what does target and chrony say? This is where the Lab Radar is good, it lets you see the downrange velocity.
They will get to 200 yards, it will just take them longer. They will shed velocity faster. Wind affects them more as it has longer to work on them. Physics matters.
However, if anyone here is gonna try it and see what happens it will be you. That isn’t a dig, it is a compliment. Would be an interesting comparison to see. Same mould, same load, what does target and chrony say? This is where the Lab Radar is good, it lets you see the downrange velocity.
I've been shooting 8" twist 300BOs since 2014, and have shot cast exclusively. Most shooting has been done with the Lee 155 and TL160, both lubed and cast. The 8" twist is no issue for running either of those bullets full speed. I have friends who also have 300BOs, 7", 8", and 10" twist. We've shot lighter and heavier bullets, all supersonic, and the 8" twist doesn't seem to be a hindrance. The 10" twist barrel was ordered and expected to be superior, but hasn't shot cast AS WELL as his 8" twist Hardened Arms.
I bought a 12 twist Wilson 7.62x40 thinking it would be superior due to "kinder twist" and 5-6gr increase in powder capacity, but it has yet to prove its worth in either regard. Velocity increase is minimal, and accuracy hasn't been as good. The 300Ham'r was designed for jacketed bullets, so expect more of the same.
As for a longer barrel in 300BO. There is only modest velocity increase in barrels beyond 16". Spend some time on the 300 Blackout forum and you'll see that some folks have spent a lot of time getting the most from the 7.62x35. Some guys are experimenting with as quick as 1-5" barrels!
I bought a 12 twist Wilson 7.62x40 thinking it would be superior due to "kinder twist" and 5-6gr increase in powder capacity, but it has yet to prove its worth in either regard. Velocity increase is minimal, and accuracy hasn't been as good. The 300Ham'r was designed for jacketed bullets, so expect more of the same.
As for a longer barrel in 300BO. There is only modest velocity increase in barrels beyond 16". Spend some time on the 300 Blackout forum and you'll see that some folks have spent a lot of time getting the most from the 7.62x35. Some guys are experimenting with as quick as 1-5" barrels!
CWLONGSHOT
Well-Known Member
I started shooting my first BO in 2012. I took all avalible bullets and milled them in half to get a better idea what I might expect. This was long before any online support for the cartritage.
(Pic's here)
I used it on game and found some was better then others. Some substantially. A few were seemingly made perfectly for attainable velocity on tap.
Most all shot MOA or better.
Next was cast and altho it shot adequately it was mo where near the accuracy of its C&C BROTHERS. That was u till I started with sub velocitys and heavy bullets. The modified LEE was first glimpse at what might be there. Then a batch of gifted Arsenal 250g and finally the NOE slick side 247g bullet. This one is aces so far and I have only shot two powders!! Imr4198 is my current choice.
The HAM'r is new late last year and altho is very accurate with C&C has not yet been tested with cast. Now talking with Brad Im itching ta try some ZINC!
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