.308 surplus spec

[Madball13]

I looking to load 2 kinds of .308, 168 grain match bullets and 147 grain surplus. I measured the OAL of some surplus ammo i have on hand and it seems to be pretty standard around 2.7 and I'm wondering if anyone has tried this or would know approx what fps surplus ammo cruises at.
Thanks,
MB

 

[Snapshot]

I measured the OAL of some surplus ammo i have on hand and it seems to be pretty standard around 2.7 and I'm wondering if anyone has tried this or would know approx what fps surplus ammo cruises at.
Thanks,
MB

Something doesn't seem right here. You're worried about the OAL of some unknown surplus. Why? That's one of the last things to worry about when reloading. You also appear to be under the impression that all surplus moves at the same speed. Even if you told us what kind of surplus (USA, Russian, Lithuanian....) that would still be a dangerous assumption.

 

[Madball13]

Something doesn't seem right here. You're worried about the OAL of some unknown surplus. Why? That's one of the last things to worry about when reloading. You also appear to be under the impression that all surplus moves at the same speed. Even if you told us what kind of surplus (USA, Russian, Lithuanian....) that would still be a dangerous assumption.

I would like to recreate as close as possible surplus ammo with the intention of sighting my rifle in and having reloads match as close as possible. the reason i mentioned the OAL is my rifle seems to like the surplus OAL. I have shot South African and S&B so far and those seem to be pretty accurate for my M1A. Thoughts?

 

[KMM696]

Cruffler.com Firearms Technical Trivia June 2001

The table lists 7.62 ammo by country - the cartridge looks like it was defined dimensionally by NATO, but didn't have consistent ballistics from country to country. According to the article, they fixed that when they defined 5.56 NATO standards.

You should be able to use the 2.790" OAL that their 'typical 7.62' measures out to - SAAMI lists 2.800" as max OAL for 308 Win, so you're under that. As far as speed, since you know that SA and S&B work well for you, I'd chrono some of those and use that as your goal.

If I were looking to duplicate an existing surplus cartridge, I would measure the speed of the loads I was duplicating, load my way up to that speed with one of the powders that the M1A likes, and then start adjusting OAL and bullet selection for best accuracy and reliability in my rifle, not to match the surplus stuff. That should leave me with the same sight settings between my reloads and the surplus ammo, and hopefully a more accurate load than the military was satisfied with.

It might be difficult to match trajectories between the 147 gr surplus and 168 Matchkings, especially at longer ranges. I haven't tried anything like that.

 

[Madball13]

Kevin,
Thanks, very helpful. I plan on using the 168 grain bullets with the scope and iron sight with the surplus and figuring out the POI for the surplus ammo w/ the scope. I was hoping not to have to chrono but it looks like i will have to.

 

[Madball13]

Cruffler.com Firearms Technical Trivia June 2001

Wow, i looked at this after i posted before, great info!

 

[Snapshot]

I was hoping not to have to chrono but it looks like i will have to.

The more I read from you the more I strongly suggest you do some more homework before attempting to load this ammo. There are some problems with what you are attempting.

Problem #1 with your project is that you are using 308 load data for an M14. M14's are not chambered for 308. They are chambered for 7.62 nato. Physically they are close enough that they will both fit but chamber pressures in a 308 are higher then 7.62 nato. In short, you do NOT want to use 308's in a 7.62. When consulting load data for 308, start off at the minimum charge and never go higher then the half way mark until you have sat down with a Chrony and tested your loads. Never load rounds hotter then factory 7.62 nato rounds.

Next: Most M14's (which is what an M1A is) have a 1:12 twist. This means that the longest bullet you want to use is 1.186 for velocities under 2800 fps or 1.423 for velocities over 2800 fps. See here:
http://northeastshooters.com/vbulletin/showthread.php?p=582978&highlight=greenhill#post582978

You are attempting to use 168 grain bullets which, depending on which ones you are using, are -at best- on the ragged edge of usability in an M14.... if not completely over the edge. According to my data, the Sierra 165gr HPBT (1.165 inches) and the Nosler 168gr HPBT (1.175 inches) are the longest you should be using in that rifle. And that's if you have a 1:12 twist. If you have one with a 1:13 or 1:14 twist then even those are too long. You could use longer if you can get the round up over 2800fps but to do that, you might be pushing the limits of the rated pressure of the nato chamber. Though I personally hadn't gotten that far in testing my M14 so I can't say for sure.

Next, you are using the term OAL in a context that doens't seem to make sense unless you are worried about reliable feeding. If feeding is an issue then yes, OAL is important. Otherwise the individual load will dictate your OAL. The accuracy that your rifle can attain doesn't care about OAL. As long as it can fit into the chamber, your OAL could be anywhere within several hundreths or even 10th's of an inch and still work just as accurately as the mil-surp stuff. That's why in reload manuals, each individual load has it's own OAL entry....because they vary that much from round to round.

Speaking of the surplus ammo. I've experimented with the South African. It's marked as 147 grains but my tests show it to actually be 142.7 grains. It has 43 grains of an unknown powder and a FMJ boat tailed bullet that is 1.135 in length. It's accuracy isn't bad but it's not really something you should be striving for. My hand loaded 150 grain speer boat tail FMJ's (1.1 inch) walked all over the S/A stuff.

 

[bpm990d]

There is nothing ragged edge about using 168 Sierras or 175 Sierras in an M-14. M852 was loaded with 168 Sierras and in the 80s and 90s there were tens of thousands of shooters that shot them at High Power matches. M118 Match & M118 Special Ball was loaded with 173s and M118LR is loaded with 175 Sierras. All of them are used in M-14s with 12 twist barrels and TM 43-0001-27 Army Ammunition Data Sheets specifically states that they are for use in M-14s.

B

 

[Snapshot]

There is nothing ragged edge about using 168 Sierras or 175 Sierras in an M-14. M852 was loaded with 168 Sierras and in the 80s and 90s there were tens of thousands of shooters that shot them at High Power matches.

With the Sierras that is correct. However we don't know what he's using. If he tries to load, for example, a CT 160, Barnes TSX 168 or some surplus M2 163gr AP in there, he's going to have a target full of keyholes. (again, this is assuming he keeps it under 2800fps)

 

[jpattersonnh]

If you are looking to reload for a 7.62x51 Nato using modern components, all will not work well. Start by backing down 10% on .308 load data. Next issue is a heavy bullet. If you are shooting a semi you have another factor to toss in. The receiver. If your load is to hot for your rifle(really tossing the brass), after backing it down 10%, you may have to go to 12% reduction. I stay w/ 150gr in my Semis. I do believe there is a 152gr match bullet that would fit the bill. My distance rifles are all bolt.