Is a 180 grain bullet harder on a semi-auto than a 150?

[Bushman]

That was a comment that I heard at the range a couple weeks back and I wonder if it could be true? I know that a 180 grain will recoil a little more than a lighter bullet, but it is the breach bolt guide ramp section that would be the first to go on my son's M742. Do you think that using a heavier bullet in that rifle would be harder on it?

[GF.]

JMO - more recoil is definitely harder on the shooter, so why not 'harder' on the rifle as well?

But that's not really the issue, is it? The question is whether the rifle was engineered and built to withstand that kind of treatment on a regular basis, and I'd be willing to bet that Remington designed the rifle around the 180 and even 200-grain (& up!) bullets that were a lot more fashionable as 'brush-busters' back when those rifles first came out.

Second thought is that while it might be possible to wear out a rifle a little quicker using the heftier slugs, very few of us will ever be so fortunate as to have to worry about it.

So most important is the question of whether the rifle and the shooter both prefer the heavier slugs to the lighter ones, and if 'raking' shots are to be contemplated, then maybe the 180s are the better choice overall.....

[Bushman]

Exactly what I was thinking about him using heavier bullets. The Remington M742 is one of the shortest lifespan rifles out there they tell me and when those rails are worn, it becomes a throw away rifle. Most guys that have those are not into pounding a bunch of rounds out of them other than to confirm that the sights are still on from last year. For that it lasts good enough for the average deer hunter. You make a good point about a .30-06 M742 being designed around a 180 grain bullet. Back in the old days no one that I knew of ever used anything other than a 180 grain bullet out of a .30-06 for deer hunting around here. 150's were for long range out west.

[dave-t.]

I think pressure is pressure, and both light and heavy bullets have their limits on how much they can be pushed within the boundries of what the cartridge case can take. If both are loaded to 50k, it doesn't matter if one is a 130grn going 3200fps, and the other is a 220grn going 2400fps. The pressure is what I would be worried about more than the bullet weight.

To throw a wrentch, which gass pressure would be the fastest and hardest on the action, a fast powder pushing a light bullet or a slow powder pushing a heavy bullet?

If we're talking factory loads, then I wouldn't worry one bit about it.

[Hi Ball]

Bushman I don't think you have a think to worry about with that model 742 Remington! If it is still shooting today, it will keep right on trucking down the road regardless of 180 verses 150 grain bullets. I am positive they took all that bullet weight into consideration. I had a friend who used to shoot nothing but those Winchester 220 grain round nosed bullets out of his M-742 and it later went to his son who still has the gun and shoots it with handloaded 165 grn bullet. Now that gun was made back in 1964 according to the serial number.:)

[Bushman]

Yes, I think that Dave nailed it with the pressure explanation. I do see where Federal just introduced two new offerings in their budget priced American Eagle line specifically for the M1 Garand .30-06 and the M1A 7.62x51 rounds that are said to be tailored to the gas system designs of those two rifles. I knew that you were not supposed to use the High Energy loads in the sporting semi-autos, but I didn't know that the M1 and M1A used any kind of a different gas system that needed different pressure profile loads.

My old .308 M742 carbine is one of the first models from the early 1960's after they dropped the M740 and it has that Tootsy Roll grooved forearm which rather sets it apart from the later ones with the pressed checkering. I sure don't know why they never made the .308 in the carbine version in later years instead of the .30-06 as the .308 seems like a better choice for a carbine with a shorter action, less weight and less recoil. Mine has never given me a lick of trouble. A specialized meat gun to be sure, but given the Mother Hubbard status of my freezer, I wish that I would have brought it out this last deer season instead. I must have shot that bolt action buck that got away at least a thousand times in my imagination since deer season.

The 180's might be a moot point for my son's .30-06 anyway as I'm going back to Hornady Custom 165 Interlocks for my .308 and I see no reason that they shouldn't do a similar great job in my son's .30-06 as well.

[Ol` Joe]

Pressure at the gas port on gas operated semi-autos is the demon that Federal and the others are trying to beat. Slow powders take time to get a head of steam up but, keep the pressures at high levels farther down the barrel. The action is designed to operate at a certain pressure range in the Garand and other old guns. The loads of the day were built around what today are medium to faster powders. If the gas pressure is too much at the port it can bend or break the operating rod of these rifles
The Browning and other late model rifles are not as affected by the powder used but, it still isn`t a good idea to use some of the "HI Energy" or "Light Mag" loads in them

[MOGC]

I wouldn't do anything to place unnecessary pressure on a Remington semi-auto. They have enough problems with receiver bolt rail and guide chattering anyway.

[M99ER]

Something you aren't considering is that when fired, the round swells and seals the chamber. The action does not begin rearward travel until the pressure reduces to a point that the case can then shrink enough for friction to stop holding it in place. Plus as Dave mentioned above with speeds of the powder, there should be little difference in action performance. Perceived recoil is from the original pressurization and thrust, not the movement of the action.