CIP length should, we are going to test that very soon! J A outdoors sells them as well. We manufacture them.
18-20" 300 RUM: change my mind..
- Thread starter 7.62 Gunner
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North Idaho Hunter
Well-Known Member
Yes - Anti's can be worked over for the UM DBM kit.
We have a very good smith on hand that makes quick work of these modifications. Very reasonably priced as well.
JamesWilson5
Well-Known Member
I would go 300 win just because even with that your just burning powder in the air . I personally own a win mag and all the 30 in weatherby and the ultra mag even the win or the 300 weatherby cant get mag velocity from a 24 that's why they use 308 06 or wsm is less powder faster burning powder to get decent results
Ernie
SPONSOR
Everyone needs to go the way they want, but most here are looking for a performance level, not efficiency.
Let me just say that in 15-18 inch barrels, when you increase case capacity, faster MV's will happen.
I don't lose accuracy.
I don't use faster powders.
Let me just say that in 15-18 inch barrels, when you increase case capacity, faster MV's will happen.
I don't lose accuracy.
I don't use faster powders.
JamesWilson5
Well-Known Member
There a good video of a guy cutting 1 inch at a time off barrel it does make a difference I mean if it didn't if not I can tell u a simple test take a 357 mag fast. Pistol powder right shoot a snub nose through chronograph then with same load with a 4 inch barrel only 2 inches diff one slow one is fast point is doesn't matter if u have a pound of powder it only going to burn a certain amount .
codyadams
Well-Known Member
Most of this is incorrect. Even in a 300 rum using something like N570, all the powder is burned in around 18 inches, reference quick load if you need. The extra barrel length just gives more time for the energy to be imparted on the bullet. And no, a 30-06 or a 308 or wsm won't even come close to comparing to a 30 nosler, prc or rum of the same barrel length, reguardless of the length. And they aren't really that much more efficient with short barrels. In all of them, you generally loose 20-35 fps per inch. I have multiple rifles with 20" or less barrels, and have seen the velocity differences from 30" barrels down. Once you get below 20", you start to get closer to 30-40 fps per inch, in pretty much any high power cartridge.
JamesWilson5
Well-Known Member
That's good last time I tried I shot a poster boards and painted them black with unburned powder
Ernie
SPONSOR
My 18" 300 Norma is so "inefficient" yet it's still slingin 225s faster than a 24" 300 win mag lol
7.62 Gunner
Well-Known Member
Good to know, you're talking worked over for the UM 3.95 mags right?
If you're in North Idaho I'm not too far south of you
7.62 Gunner
Well-Known Member
Durbis..
might as well shoot a .308 at 18", it'll be just as fast with half the powder
I think he thinks our velocity numbers are inflated like joe bidens gas prices lolDurbis..
might as well shoot a .308 at 18", it'll be just as fast with half the powder
codyadams
Well-Known Member
A 40" barrel will leave powder burns at close range. A poster board is less than scientific. You certainly gain velocity with a longer barrel, that is an absolute given, but it has nothing to do with a complete powder burn. It has to do with the available energy from the burned powder having more time (barrel length) to put that energy into the bullet.
I see more unburned powder in a 45-70 barrel after each shot than I've ever seen from a short barreled magnum.
I've taken the short barrel magnum concept to the extreme, and I know Ernie has as well. I've never really seen the increase in muzzle flash, or any unburned powder flying out of the barrel. Just for fun, this video compares the same load in a 30" barrel and a 20" barrel. These guns are both shooting 140gr of H50bmg and a 300gr OTM. There aren't a lot of powders out there slower than H50bmg, so this is a pretty good test of the short barrel/slow powder myth.
Here's a less extreme example, but still a good one. This is 76.5gr of H4350 behind a 250gr bullet from an 18" barrel. The muzzle flash really isn't that significant.
I'll bring a big white sheet the next time I bring out the 338/408 Improved pistol. I might need to bring 10-15 tent stakes to try and hold the sheet down, but I'll lay it out in front of the muzzle to see if there's any unburned powder on the ground. I've never done that, so it's a good idea for a test.
