New project!! .30 LR Rifle

[JJMoody]

Swamplord's razor is pretty cool, the headhunter in a single shot configuration looks pretty cool too. Mag bf cannons, head stamped brass. 'Bout all the info out there https://m.facebook.com/375Mercenary/?ref=bookmarks

 

[Calvin45]

What about the bullet placed inside the powder column?
I have read that this, unlike the 300 PRC, deteriorates performance. "The bullet can be bent or pushed off-axis, forcing the bullet to yaw prior to contact the barrel rifling".
A perfectly designed case would have the top of the bullet's boattail sitting right at the case's neck and shoulder junction. This keeps the bullet's bearing surface above the joint, but also keeps the bullet out of the powder column.
This is not the case with the 300 Rum case, which at a glance looks like the bullet gets into the case.
I am not sure how much this will affect the accuracy

I can certainly see the theoretical reasons this might be the case but have yet to observe any field results suggesting it's actually a problem to seat deep. The .300 win mag with its stubby little neck and prohibitive coal restrictions has been delivering the goods with long projectiles at long range seated deep for a long time now, and continues to do so (the new-ish 220 smk load adopted by the us navy - I think it's the navy anyways - ought to shed some further light on the discrepancy between theoretical disadvantages and actual problems). My own accuracy load in .300 win with a 225 eld. Suffice to say it protrudes into the case a good bit, even while being too long to feed from the magazine.

 

[Velvet]

300 PRC, 30-28 Nosler, 300 Norma, or 300 Norma Imp. I have them all except the 300 PRC. The 30-28 Nosler will push Berger 215 Hybrids 3050 fps, the 300 Norma with at straight 30" barrel with push the 215 Hybrids at 3150 fps, and the 300 Norma Imp will push the 215 Hybrid at 3150 in a Proof 26" barrel. Super accurate and easy to tune.

Good luck!

Precise info!!, what powder are you using for this cartridges?

 

[Velvet]

I have a 300 RUM build on a blue printed Remington 700 action and 30 inch stainless Lothor,Walther barrel in a 1-8 twist. Macmillan stock, Jewel trigger, Wyatt's long box magazine. It shoots 210gr Nosler Accubond LR @ 3308fps with. 311moa at 200 yards. Nightforce mount, rings and ATACR 7 X 35 X 56. Extra barrel length will increase your speed dramatically but I'm not sure about going to 32 inches as most powder will be gone by 28". It would behoove you to check out the burn rate of the powders you intend using before getting a barrel over 30 inches.
Good luck with your build!

Good observation!! the one you do in relation to the length of the barrel. I'm going to check it with quickload to get an idea at what length the powder finishes burning.
Now, please tell me with what powder are you achieving those speeds ...... it is to fly old wigs

 

[Velvet]

All good choices. My vote is for the 30 Sherman Magnum. Rich has dies and ADG brass in stock. 245gr Berger at 3000fps. Can shoot factory 300 PRC if you want (at ~2880 w/ 225 ELDM). Will feed from a CIP length mag. The 300 RUM will beat it, but not by much, and in order to do so it'll have to single feed. If I didn't already have a 7mm Sherman Short and a 338 Sherman Short being built that's what I'd do...but I like short actions.

The truth is that the sherman has several virtues, which have already been listed. But I still do not have the "verifiable" certainty that the 220+ can be pushed to more than 3000ps with H1000 and without excessive pressure ... which is one of the objectives of the project.

 

[Chase723]

I think it would do it. If not, it would be real close. In a 28" barrel Rich shot the 245gr Berger at 2960 w/ H1000. 3040 w/ RL33.

 

[Velvet]

I can certainly see the theoretical reasons this might be the case but have yet to observe any field results suggesting it's actually a problem to seat deep. The .300 win mag with its stubby little neck and prohibitive coal restrictions has been delivering the goods with long projectiles at long range seated deep for a long time now, and continues to do so (the new-ish 220 smk load adopted by the us navy - I think it's the navy anyways - ought to shed some further light on the discrepancy between theoretical disadvantages and actual problems). My own accuracy load in .300 win with a 225 eld. Suffice to say it protrudes into the case a good bit, even while being too long to feed from the magazine.

I agree with everything you say, especially with what you express in relation to what is the theory, and what is the practice later.
I believe that one has to prove and draw oneself conclusions.
But, there is indisputable data:
For a 300win SAAMI chamber, the OAL is severely limited (for those long/heavy bullets). Look at the photo, and tell me if it is not ridiculous what the bullet gets inside. That dummy cartridge, with the bullet kissing lands, is 3.5105" OAL.
If one were only guided by the theory, perhaps you would think that it is not a good idea to use that long bullet, but if you look at the target, the result is good. What I would like to do would be to bring those 2750ps to 3000ps or more. That load is with 73.5gn of H1000, CCI250, old LAPUA cases.

 

[Velvet]

I think it would do it. If not, it would be real close. In a 28" barrel Rich shot the 245gr Berger at 2960 w/ H1000. 3040 w/ RL33.

Good info Sir, thanks.

 

[Calvin45]

I agree with everything you say, especially with what you express in relation to what is the theory, and what is the practice later.
I believe that one has to prove and draw oneself conclusions.
But, there is indisputable data:
For a 300win SAAMI chamber, the OAL is severely limited (for those long/heavy bullets). Look at the photo, and tell me if it is not ridiculous what the bullet gets inside. That dummy cartridge, with the bullet kissing lands, is 3.5105" OAL.
If one were only guided by the theory, perhaps you would think that it is not a good idea to use that long bullet, but if you look at the target, the result is good. What I would like to do would be to bring those 2750ps to 3000ps or more. That load is with 73.5gn of H1000, CCI250, old LAPUA cases.

Oh for sure it seems ridiculous, I've done that many times, looked at a loaded .300 win round beside a projectile to see how deep it goes and shook my head a bit. My load I mentioned "compresses" (more like crushes) 79 grains of imr 8133 under that 225! Went up to 80 too, but there was only 15 FPS gain in velocity, and a widening of es numbers, going from 79 to 80, so 79 it is.

 

[Gone Ballistic]

Good observation!! the one you do in relation to the length of the barrel. I'm going to check it with quickload to get an idea at what length the powder finishes burning.
Now, please tell me with what powder are you achieving those speeds ...... it is to fly old wigs

90.3 gr. RL-25. The key to getting the 210 Accubond to shoot tightest groups for me (previously shooting Berger's at -.002 off L&G's) was to set them in deep to SAMI standards OAL 3.6" . Had fits until I tried this with Accubond bullets of 200 grains up. Don't know if you will be I suggest this to anyone having problems with this bullet.

 

[Velvet]

90.3 gr. RL-25

Amazing numbers!!!!, 3300ps with 210gn!!. 30"
it is to be expected that with the 220gn bullets, 26" barrel, and H1000, that speed will drop considerably, but I don't think less than 3000.

 

[Gone Ballistic]

Amazing numbers!!!!, 3300ps with 210gn!!. 30"
it is to be expected that with the 220gn bullets, 26" barrel, and H1000, that speed will drop considerably, but I don't think less than 3000.

I was doing 3391 avg with the 200's before the 210's came out using Retumbo. I pushed the 210 with Retumbo to 3212 but wasn't happy with my groups compared to the 200's which I thought would be better with the additional BC. So I started experimenting with new powders and RL-25 did it well. My top hottest broke 3400fps but groups were terrible.

 

[Velvet]

I was doing 3391 avg with the 200's before the 210's came out using Retumbo. I pushed the 210 with Retumbo to 3212 but wasn't happy with my groups compared to the 200's which I thought would be better with the additional BC. So I started experimenting with new powders and RL-25 did it well. My top hottest broke 3400fps but groups were terrible.

again, terrific speeds.....
look where it ends up burning for your solution. I don't have the 210gn AB in the list. Definitely not need 32", with 26" I will be fine

 

[Gone Ballistic]

again, terrific speeds.....
look where it ends up burning for your solution. I don't have the 210gn AB in the list. Definitely not need 32", with 26" I will be fine

If you look at the OAL shown on this chart you will also see the Accubond needs seating a couple of thousandths deeper than SAAMI specs.