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30 Cal
- Thread starter rfxcasey
- Start date
condor bravo
New member
Not completely successfully across the board. The '06 and .300 Blackout both use .308 diameter bullets while the x39 and x54 call for slightly oversized bullets. Bore sizes for the latter two between different rifles can vary. Check your reloading manuals for the appropriate bullet sizes. Loading dies would not be compatible.
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Also the 7.62×39 usually uses a lighter bullet than is commonly fired in the 7.62×54, as heavier ones consume too much of the powder space in the little case and the gas guns have gas systems made for these bullet weights.
Your best bet for bullet diameter is always to slug your bores and measure their actual groove diameters. Beartooth Bullets, LBT, Meister bullets, Missouri Bullets, and NECO all make slugging kits. You can also use Hornady lead balls bumped up or rolled down as needed. Always use pure lead and not a casting alloy for slugs, and always use an OD thimble micrometer with 0.0001" resolution rather than a caliper for measuring the land diameter for accuracy (unless you are very experienced and skilled with a good quality dial caliper and can read between the graduations reliably). Unfortunately, if you have an odd number of lands in your bore, you will need a V-anvil micrometer, with 108° V for 5 groove and 60° for 3-groove bullets. Dardas Cast Bullets will make this measurement for you if you do not have these instruments. They do not sell a slugging kit, however (not that I could find on their site, anyhow), so this is just a service they offer in order to be able to recommend the right cast bullet for your gun, assuming you shoot cast bullets in it.
Your best bet for bullet diameter is always to slug your bores and measure their actual groove diameters. Beartooth Bullets, LBT, Meister bullets, Missouri Bullets, and NECO all make slugging kits. You can also use Hornady lead balls bumped up or rolled down as needed. Always use pure lead and not a casting alloy for slugs, and always use an OD thimble micrometer with 0.0001" resolution rather than a caliper for measuring the land diameter for accuracy (unless you are very experienced and skilled with a good quality dial caliper and can read between the graduations reliably). Unfortunately, if you have an odd number of lands in your bore, you will need a V-anvil micrometer, with 108° V for 5 groove and 60° for 3-groove bullets. Dardas Cast Bullets will make this measurement for you if you do not have these instruments. They do not sell a slugging kit, however (not that I could find on their site, anyhow), so this is just a service they offer in order to be able to recommend the right cast bullet for your gun, assuming you shoot cast bullets in it.
If you can't use the same projectiles and dies for all 4 calibers, all is not lost. It's likely that you can use the same powder for at least 3 of the 4 (I'm not sure about the .300 Blackout). I would look at powders that burn like IMR-3031 or slower. I think one of the 4895 powders would work very well. Just a thought.
Start by reading a copy of The ABC's of Reloading from cover to cover.
Both 7.62 x 39 and 7.62 x 54R require .311" bullets. They're not 'slightly oversized'. Like Unclenick says, both use very different bullet weights too.
The "7.62" in a cartridge name is not the bullet diameter. It's the nominal bore diameter. That's the diameter of the hole drilled through the barrel blank before there's any rifling.
A slugging kit is a 1/4" brass rod, a plastic mallet and a 0-1 micrometer.
0.0001" resolution is unnecessary. A V-anvil micrometer isn't necessary either.
Both 7.62 x 39 and 7.62 x 54R require .311" bullets. They're not 'slightly oversized'. Like Unclenick says, both use very different bullet weights too.
The "7.62" in a cartridge name is not the bullet diameter. It's the nominal bore diameter. That's the diameter of the hole drilled through the barrel blank before there's any rifling.
A slugging kit is a 1/4" brass rod, a plastic mallet and a 0-1 micrometer.
0.0001" resolution is unnecessary. A V-anvil micrometer isn't necessary either.
The '06 and .300 Blackout both use .308 diameter bullets
Where can I find more information on this? Thanks for all the info. If I'm not mistaken I thought the 300 Blk used pistol powder? Is there any difference between 300 Blk and 300 ACC?
condor bravo
New member
No, the acc and blk are the same; also known as 7.62x35. Yes, some handgun powders are used, like Unique and w231, but mostly rifle powders. As indicated above, if the x39 or x54 are to be used seriously, the bore should be slugged to determine correct bullet diameter rather than to rely on a standard .311, although the latter would likely be fine.
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The light powder charges are to avoid sending the bullet supersonic, which makes a sonic crack going downrange that sounds about like a .22 rimfire pistol being fired if it goes past you in the target pits. That makes any supression scheme a lot less successful.
The reason I recommended an inexpensive thimble micrometer is I once allowed five reloading newbies to measure a slug both with calipers and a micrometer and the results they reported for the caliper measurements varied 0.002", while their micrometer measurements agreed within 0.0004", and averaged 0.001" larger than their caliper measurements. I don't know what experience you may or may not have with measuring instruments, but because that 0.001" average distance is greater than I would want to allow for a cast bullet diameter difference, I find the micrometer a better recommendation. At under $15, it's not like the one I linked to will break the bank, either.
The reason I recommended an inexpensive thimble micrometer is I once allowed five reloading newbies to measure a slug both with calipers and a micrometer and the results they reported for the caliper measurements varied 0.002", while their micrometer measurements agreed within 0.0004", and averaged 0.001" larger than their caliper measurements. I don't know what experience you may or may not have with measuring instruments, but because that 0.001" average distance is greater than I would want to allow for a cast bullet diameter difference, I find the micrometer a better recommendation. At under $15, it's not like the one I linked to will break the bank, either.
Gunplummer
New member
Slugging bores is pretty much a waste of time when using copper jacketed bullets. A plus or minus on a bore diameter compared to bullet diameter is no big deal. The REAL trouble comes from the neck diameter. If you squeeze .310-.312 bullets into a rifle chamber that was cut for a .308 bullet, you probably will increase the initial pressure when fired. I have been messing around with CUT RIFLED .312 barrels for a long time. I had piles of them and used to experiment with them. I have had two Arisakas I bought at yard sales that were re-cut to .300 Savage. Both guns shot exceptionally well with factory ammo, better than a lot of new rifles. I still have an Arisaka I reworked to 7.62x39 and I use .308 bullets because they shoot better than the .312 bullets from various companies. That is one of the few guns I own that I will take a head shot on a deer with. I have had a .30 Mauser (.303), .303 Brit., and all kinds of Arisakas and Russian bolt guns. Reloading die sets for .310-.312 cartridges used to come with two different sized (.308 and .312) expander balls. You don't sound as if you are going to some kind of national shooting event, so bullet diameter is not all that important if under size a little.
Reason I ask is I have a Marlin Xl7 in 30 06 and 2 ARs in 5.56. It would be great to be able to use the same projectiles for reloading both the 06 and a 300 Blk if I choose to get one. From what I'm reading the 5.56 casings can be easily cut down for use in 300 Blk reloading.
Gunplumber,
Yeah, but some of the 7.62×54 barrels aren't 0.312". I've seen 0.313", 0.314", 0.315, and 0.318" reported after slugging (though I don't know, personally, how good the measuring job was). It really seems to depend who made the gun and when. With a bore as wide as 0.318", all you can recommend is getting the throat opened for .321" bullets and shooting those.
You can usually let pressure bump a jacketed bullet up 0.001". A lot of British competitors used to swear by .309" bores for .308 chambered rifles, though it seems to me they were still applying grease to them at the time. Getting much bigger than that, though. I note that Hornady makes 0.310", 0.3105" and 0.312" bullets, the later two being intended for the .303 British, which also comes in more than one bore diameter.
Rfxcasey,
If you look at the bullet load selections at Hodgdon's load information site, you'll see the .300 AAC Blackout can, indeed, use many of the same bullets as .30-06.
Yeah, but some of the 7.62×54 barrels aren't 0.312". I've seen 0.313", 0.314", 0.315, and 0.318" reported after slugging (though I don't know, personally, how good the measuring job was). It really seems to depend who made the gun and when. With a bore as wide as 0.318", all you can recommend is getting the throat opened for .321" bullets and shooting those.
You can usually let pressure bump a jacketed bullet up 0.001". A lot of British competitors used to swear by .309" bores for .308 chambered rifles, though it seems to me they were still applying grease to them at the time. Getting much bigger than that, though. I note that Hornady makes 0.310", 0.3105" and 0.312" bullets, the later two being intended for the .303 British, which also comes in more than one bore diameter.
Rfxcasey,
If you look at the bullet load selections at Hodgdon's load information site, you'll see the .300 AAC Blackout can, indeed, use many of the same bullets as .30-06.
Gunplummer
New member
That is like chasing your tail. You try a couple different bullet weights and styles, and if it does not work, you scrap the barrel. Most of the time with military guns the accuracy problem is wrong bullet configuration or weight. I still have, and hunt with, a 6.5 Arisaka I re-cut to 6.5x55. With 140 grain BTS bullets it will key hole a target at 50 yards. What I did not realize was that very early 6.5s had a different twist rate. They used some unbelievable heavy bullets for a 6.5. I am not sure, but I think they were 190 grain. I loaded up some 160 grains and they shoot great. I had the same problem with an 8 MM MG-34 barrel. Had to load up heavy bullets, although it was not bad enough to key hole. All you can do is try different bullets and see what happens. That is what reloading is all about.
I don't know about Hornady making bullets in .0005 increments. I have used Hornady a lot over the years and I would have to say they have a hard time holding .0005. I can not complain, Hornadys generally shoot O.K. for me.
I don't know about Hornady making bullets in .0005 increments. I have used Hornady a lot over the years and I would have to say they have a hard time holding .0005. I can not complain, Hornadys generally shoot O.K. for me.