Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Based on Specifications, there IS a difference between 7.62NATO and 308Win.
The former is tightly speced around a 147gr bullet at a nominal 2700fps. To function in all manner of NATO bang sticks. SAAMI puts the 308W at 2850fps so pressures are significantly higher. It is common for target shooters to run velocites even higher.
Powders have changed over the years but in all instances I am aware of, lean towards the 'fast' end of the burn range.
That is really important because managing port pressure is key to longevity and also accuracy.
The M305 gas/recoil system is a balancing act and is really finicky. Yes, you can fire 308W in the rifle with no obvious ill effect mechanically but I bet accuracy stinks with enormous vertical stringing.
When the load is balanced for the gas system AND barrel, you can get these rifles to shoot superbly. If your brass is ejecting more then a few feet from the rifle, you are running it too hard for best performance. If you see dings and dents on the case body, same thing.
Going to a heavier bullet WILL tax the op rod and other parts. Will it fail in a box or two, of course not. This is still a mondo built steel action. However, ongoing use will show up in increased wear and tear.
As for headspace, that can vary ALOT from rifle to rifle/lot to lot. I have yet to see or hear about a NORC going too far OVER NATO spec which would lead to head separation on the first firing. The chambers are generous for sure but that is a good thing in a battle rifle.
Shooting factory or surplus ammo shouldn't pose any issues if within NATO specs. bolt action factory 308W ammo may split if the chamber is too big.
If you reload, you just have to work around this. mysticplayer.netfirms.com has my thoughts and info on reloading for these rifles. Follow the instructions carefully and to the letter and you will no issues with your M305.
Enjoy the rifle within its design specs and it will reward you with superb accuracy, dead reliability and very long life.
Jerry
The former is tightly speced around a 147gr bullet at a nominal 2700fps. To function in all manner of NATO bang sticks. SAAMI puts the 308W at 2850fps so pressures are significantly higher. It is common for target shooters to run velocites even higher.
Powders have changed over the years but in all instances I am aware of, lean towards the 'fast' end of the burn range.
That is really important because managing port pressure is key to longevity and also accuracy.
The M305 gas/recoil system is a balancing act and is really finicky. Yes, you can fire 308W in the rifle with no obvious ill effect mechanically but I bet accuracy stinks with enormous vertical stringing.
When the load is balanced for the gas system AND barrel, you can get these rifles to shoot superbly. If your brass is ejecting more then a few feet from the rifle, you are running it too hard for best performance. If you see dings and dents on the case body, same thing.
Going to a heavier bullet WILL tax the op rod and other parts. Will it fail in a box or two, of course not. This is still a mondo built steel action. However, ongoing use will show up in increased wear and tear.
As for headspace, that can vary ALOT from rifle to rifle/lot to lot. I have yet to see or hear about a NORC going too far OVER NATO spec which would lead to head separation on the first firing. The chambers are generous for sure but that is a good thing in a battle rifle.
Shooting factory or surplus ammo shouldn't pose any issues if within NATO specs. bolt action factory 308W ammo may split if the chamber is too big.
If you reload, you just have to work around this. mysticplayer.netfirms.com has my thoughts and info on reloading for these rifles. Follow the instructions carefully and to the letter and you will no issues with your M305.
Enjoy the rifle within its design specs and it will reward you with superb accuracy, dead reliability and very long life.
Jerry
doesn't quite do the job here 
