Talk to me about bullet weight

J-Dog · Apr 15, 2014

I did some searching and googling, but I'm not finding what I'm looking for.

We have a Sig 2022 in 9mm, and an M&P 9c. I usually shoot 115gr FMJ out of them, ,mostly Blazer Brass and Speer Lawman, but I have a few hundred rounds of 124gr FMJ of each brand. Looking around, it seems that most folks are out of stock of 115gr FMJ, but there seems to better availibility of 124gr.

So my question is, is it safe to shoot 124gr a lot? I would imagine that the heavier bullet weight would be harder to spin and put more wear and tear on the rifling and other parts. But that's just a theory.

teratos · Apr 15, 2014

I shoot mostly 147 grain. I hope there is no increased wear.

Overboost44 · Apr 15, 2014

Oh crap, can someone take all of these 62 and 75gr .223's off my hands? :sarcasm:

johnnyb2 · Apr 15, 2014

115 gr are the LEAST expensive to shoot, which is the main reason people choose them to shoot. you CANNOT hurt your gun, shooting other weight bullets. C'mon now, think about it. :-)

Melnic · Apr 15, 2014

I believe the heavier bullet should be loaded for a lower velocity.

J-Dog · Apr 15, 2014

I think I'm overthinking it.

My thinking was that a heavier bullet would not spin up as quickly as a lighter bullet when traveling down the rifling, and would wear the rifiling down quicker if you used heavier bullets exclusively as opposed to lighter bullets. But I'm probably overthinking/thinking it wrong.

Doing some more research, seems like it doesn't matter.

I know that you can shoot stuff like 147gr HP, but I always thought that that that was something people did to test things like accuracy and reliability, and they didn't run thousands of rounds of heavy bullets for just regular old target shooting.

But thinking about it more, it kinda makes sense that the bullet weight wouldn't hurt the gun, since stuff like .45ACP (which I know less than nothing about) is heavier and shoots just fine. And copper plating and lead is softer than steel, and I ponder this stuff too much.

Well, now I just feel silly.

Thanks.

J-Dog · Apr 15, 2014

Melnic said:
I believe the heavier bullet should be loaded for a lower velocity.

I thought so too, but are they? Or are they loaded the same and the difference in velocity is due to the heavier bullet not accellerating as quickly as the lighter bullet?

teratos · Apr 15, 2014

J-Dog said:
I know that you can shoot stuff like 147gr HP, but I always thought that that that was something people did to test things like accuracy and reliability, and they didn't run thousands of rounds of heavy bullets for just regular old target shooting.

You do when you are shooting suppressed.....

damifinowfish · Apr 15, 2014

J-Dog said:
I would imagine that the heavier bullet weight would be harder to spin and put more wear and tear on the rifling and other parts. But that's just a theory.

The relationship between barrel wear is between the amount of gun powder used and not the projectile.

stu929 · Apr 15, 2014

Lighter bullets = faster
heavy = slower

Barrel wear has more to do with heat than anything else I believe

J-Dog · Apr 15, 2014

teratos said:
You do when you are shooting suppressed.....

Good point. but aren't you shooting at a lower velocity?

J-Dog · Apr 15, 2014

damifinowfish said:
The relationship between barrel wear is between the amount of gun powder used and not the projectile.

stu929 said:
Lighter bullets = faster
heavy = slower

Barrel wear has more to do with heat than anything else I believe

Ahh. I see.
Thanks.

I was thinking about picking up a case of 9mm and wanted to make sure that I wasn't buying up a bunch of ammo that I'd regret.

Biggfoot44 · Apr 15, 2014

The answer you are looking for is essentially no difference ( presuming that all of the bulk ammo in question is standard pressure/ velocity ).

Wear on the interior of the bbl ( to only slightly simplify ) is factored by the errosion properties of the hot gasses long before the physical friction of the bullet becomes an issue. They factors of ( flame temperature , pressure curve , percentage of solids in residue , and a bunch of chemical engineering trivia ) are not redilily discernable from information available to consumers.

The "overall wear and tear" upon the gun ( to oversimplify even more ) is a factor of the momentimum ( bullet wt x velocity ) of the load being above normal/ what gun is designed for. This would be ammo designated as +P , or +P+ ( , or NATO - some of which is within SAAMI spec , and some isn't) . This can lead to increased forces upon slides , frames , locking surfaces. Some guns are specified as being *safe* with certain levels of loads , but even then wear & tear will be accelerated. [ If the ammo in question is extra hot , it will be marked , probably an bragging point , and probably pay a premimum for it ].

In the day , when +P+ 9mm was in vogue as an issue LE round , the rule of thumb in circulation was a service life of aprox half that of std pressure rounds. If you were speaking in terms of 10,000rds vs 20,000rds , many agencies considered that acceptable , as they already had replacement cycles in that range , and they desired the performance of the hotter ammo.

[ Historical note- I still like 115+P+ to this day , but more recent ammo developements has developed many good performing 124-ish gr loads at both std pressure , and +P levels. I'm just Old School.]

J-Dog · Apr 15, 2014

Interesting. Thanks!

I'm not playing with +P or anything. Just wondering about FMJ stuff for target shooting. I still use standard pressure hollow points for HD.

I didn't know about all the chemistry stuff. I thought the friction would be the bigger factor. Good to know!

Chasbo00 · Apr 15, 2014

Interesting read on barrel wear here:

http://pistol-training.com/archives/8648

Pretoria78 · Apr 16, 2014

Your SP 2022 and M&P 9C will happily gobble up 115, 124 and 147 ammo. Assuming it's manufactured in accordance with SAAMI / CIP specs, you should be GTG.

teratos · Apr 16, 2014

J-Dog said:
Good point. but aren't you shooting at a lower velocity?

Yep. Subsonic bullets are much quieter. Where I often shoot is legal, but in a place where if I shot unsuppressed would annoy neighbors and most likely prompt a call to the police. Problem solved. Shoot cool suppressed guns and annoy nobody.

IndispensableDestiny · Apr 16, 2014

J-Dog said:
I think I'm overthinking it.

You are over thinking it. Just go out and shoot.

J-Dog · Apr 16, 2014

Pretoria78 said:
Your SP 2022 and M&P 9C will happily gobble up 115, 124 and 147 ammo. Assuming it's manufactured in accordance with SAAMI / CIP specs, you should be GTG.

Gotcha. Thanks!

IndispensableDestiny said:
You are over thinking it. Just go out and shoot.

Yeah. It happens. Slow morning at work.

Talk to me about bullet weight

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