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from Stephen08 on 04.17.10
I want to clear up any miscommunication on my comment about the .308 Win. and 7.62 NATO being not interchangeable. I'm not saying the two rounds are different calibers. They both are .308 Winchester caliber, one is a commercial offering (.308 Winchester) and the other is a military labeling and loading (7.62x51mm). My comment is more of a safety issue.
Johnnie, I always experiment with loads that have the most potential by seating them at various lengths. All other factors being consistent I have found as you suggest that the distance the bullet travels to engage the rifling is significant. I use the Stoney Point system for measuring the chamber and overall length tolerated with the load. Oddly, the Model 70 sporting rifle loads were seated longer than the military load. I did not measure the military load only set my seating die to one of the hardball rounds and loaded 150 gr Speer Grand Slams up for the M1A. The Winchester Featherweight can be on the finicky side and I had messed around with various powders, bullets and finally seating depths to get it shooting well. I don't have the info with me but I believe the 150 Sierras and the Grand Slams were seated 8 to 10,000 off the rifling. The 'Mexican Match" (thanks for the new lingo Old Salts) had a considerable jump to engage the rifling and shot the best pattern at 100 yards ever fired from the rifle. You have go to be kidding, was my first thought!! I will check the velocity of those rounds in the M1A as suspect the load is travelling slower than my regular handloads. I have since sold that Winchester, replacing it with a take down Browning Lever gun in .308. I will give those mexican match rounds a try in that rifle as well.
Kody, in regards to your sporting rifle shooting your tailored loads for the M1A better. It can be your M1A has a mil-spec chambering which can have a longer throat/leade. Your sporting rifle can have a shorter leade, the bullet is closer to the lands and doesn't have to jump as far as it has to in the M1A. Do you have a OAL gauge? Check the chambers. Be interesting to know if there is a difference in dimensions.
By the way, you guys are speaking my language!
By the way, 7.62 NATO makes perfect 260 Remington and 243's, O'BABY!
I prefer military brass over commercially made. When using military brass, reduce you load by 1.5 grains to compensate for the wall thickness of the case. Pulling a 147 and seating a 150 is called Mexican Match! I pull M118 173 Grain Special Ball and seat 165 soft points and works fantastic! The 173's in turn I load for my M1 Grand which loves the bullet for 1000 yard competition as well as my M1A!
For handloading, I prefer Military Brass over commercial!
Johnnie, It is commercial ammo not the military stuff that can be loaded to higher pressures, not the reverse as you suggest. Perhaps you were thinking of the handloading issues that surface when using the thicker military cases. Your pet rifle load in the thicker case will increase pressure, to what degree is open to conjecture. However, it is wise to reduce the powder load and work up slowly watching for signs of pressure with each increment.
Old Salt has it right. I would only add that the primers on Nato or military rounds are harder than standard commercial primers. It is another factor to consider if firing commercial factory rounds from a semi automatic military firearm such as the Springfield M1A. It opens the possibility of a slamfire in which the rebounding firing pin detonates the chambering round without the shooter pulling the trigger. Fire the M1A and inspect the round that chambered after the firing. There will be a mark indicating that the firing pin has made contact. I have pulled 148 gr hardball rounds from military loads and seated quality 150 gr hunting bullets to the same overall length. In this way I avoid the pitfalls mentioned above and turn the M1A into a fine hunting rifle. Ironically, these rounds proved more accurate in my sporting rifle than the rounds I had meticulously developed by handloaded for that rifle..go figure!
WHAT IN THE WORLD ARE YOU GUYS TALKING ABOUT!
Here's the scoop from a 2nd Generation U.S. Air Force Shooting Team Member (Retired) who specializes in this subject.
Question: Is it safe to shoot 7.62 NATO in a 308 Winchester?
The answer is yes provided the firearm is of good quality!
7.62 NATO is specially designed for Gas Operated Firearms and maximum performance.
Question: Can I shoot 308 in a a Firearm designed for 7.62 NATO?
The Answer is YES and "ONLY IF IT'S A STANDARD FACTORY LOADING". In other words, cannot be a loading such as Hornady Light Magnum. How ever, the Supreme performance can be used.
At the gas port to operate the operator rod can not exceed a certain pressure level and a load that puts excessive pressure at the gas port will cause the bolt to move faster than designed to causing damage to the receiver and breaking the extractor among other things.
FYI TO HANDOADERS!
For M1A's, M14's and M1 Garand shooters, there are only three powders I recomend and yes they work fantastic in both hunting and competition.
All three I have shot thousands of rounds and winning local, State and Regional Matches and are withing the safe operating pressure specifications.
Question: What bullet weights can I shoot in a firearm designed for 7.62 NATO?
Answer: No lighter than 150 and no heavier than a 180 grain!
Any bullet over 180 really puts a pounding on the
Any 7.62 loading can be used in a firearm chamber in 308 of good quality.
I would say no to interchangeability between the 7.62 NATO and .308 Winchester rounds due to the fact for the same reason .223 Remington and 5.56x45mm NATO are not interchangeable. It is safe to shoot .223 Remington in a rifle chambered for 5.56x45mm NATO, but not the other way around and I would apply that same reasoning to the .308 Winchester and 7.62x51mm NATO.
Why the ammo is not interchangeable is: NATO ammo is loaded to higher pressures than commercial ammo. For those who handload: NATO brass case walls are thicker reducing powder room and can increase case pressure. Though a NATO round of ammo will fire in a commercial rifle, due to the higher pressure of NATO ammo it is unsafe to use in commercial rifles.
Another thing is the rifle's chamber. A commercial rifle's chamber is different than a NATO/mil-spec chamber. The rifle throat/leade is longer in a NATO/mil-spec chambering.
If, you want to delve deeper into the subject the Internet, books, and gun magazines can give you more insight on the subject.
I will not try to give an answer when there is so much info available online. Check out the following sites:
For the record, there are probably many more sites than this, but this is a good start.
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