Heavier bullets knock down steel more reliably than lighter ones
Heavier bullets go slower, so you might not get a sonic crack - I like that, it might not matter to you.
I shot a couple boxes of 115 and then a couple WWB 124 NATO thru the tiny Sig. In such a light gun, the difference is noticeable.
I ever had anything tiny in my hands,, I can't relate to that
Go open the door to your safe. Back off and swing at it with your closed fist as hard as you can smack it. Not much, huh? Now open your hand and give it a little push. Not exactly scientific evidence but food for thought.
Isn't FG&G in your neck of the woods? The one time I was there, it looked like they carry everything under the sun. I'm just glad they're so far from me.I buy 99% of all stuff in my life in cash. It's hard to find heavier stuff locally
Only thing I've seen is 115 in bulk. Maybe I should look again, I haven't been there but twice this weekIsn't FG&G in your neck of the woods? The one time I was there, it looked like they carry everything under the sun. I'm just glad they're so far from me.
Here's my theory:
Power factor is a measure of momentum, mass times velocity. (p = m*v)
But energy is 1/2 times mass times velocity squared (ke = 1/2*m*v^2)
So a round with the same momentum but a lighter bullet must have more energy. Or, the opposite, a heavier bullet will have less energy for the same power factor. There's no perfect formula for "felt recoil" that I've ever heard, but it definitely is tied more to energy than momentum, since light bullets (higher energy) manifestly recoil with more snap than heavier bullets loaded to the same power factor (same momentum, lower energy).
Here's a chart with round numbers for common 9mm bullet weights and velocities, all around 125pf:
View attachment 57529
(Power factor computed as mass * velocity divided by a thousand. Energy computed as 1/2 mass * velocity squared divided by a million, just so the numbers are easy to compare.)
Even going from 115 to 125 is a large decrease in energy. This is anecdotally confirmed by the fact that while 115gr is virtually unheard of in competition (outside of perhaps Open, where all the rules are different), 125gr is fairly common. It is, essentially, the lightest 9mm considered realistically competitive.
Anecdotally, out of my 43 ounce Tanfoglio Stock 2, I can't tell much of a difference between 135 and 147 grain bullets. So I shoot blue 135s because I like the bullet profile.
There definitely is some diminishing returns to having energy be too low, though. Some folks dabble with 165gr bullets in 9mm, but they have never really caught on. My theory is that, past 147gr, the diminishing returns of a heavier bullet are so small (given that energy is an exponential formula) that the increased cost for negligible benefit isn't worth it.
Jeff has what you need at NC Shooter's Supply.I buy 99% of all stuff in my life in cash. It's hard to find heavier stuff locally
Back when dinos roamed and everybody shot major..175.. I loaded some .45s all to major. But JUST to major, none to spare. I loaded 152, 180, 185, 200, 215, and 230. I took them to a match in Wilmington about 1985-6, along in there. A big match, 70 plus shooters, took all day. At the end of the day I took the top 5 finishers aside, actually 2 through 6. I won but I knew what the plan was, so I stayed out. I gave each man a mixed mag of the loaded ammo to shoot. Then we did it several more times. All, to a man, said they could not tell one round from another when loaded to 175. Again, not scientific, but food for thought. All were shooting 5 inch 1911 platforms. Because, well that's what we did 30+ years ago.
Yep, if power factor is the same, recoil should be the same. For the power factors to be the same, you would apply less force to a heavier projectile versus a greater force to a lighter projectile... it's just physics...What that does not take into account is a specific power factor that you are trying to achieve. If you take your same figures you will see that the 115s=a power factor of 132.8 while the 147s =a power factor of 147. If you loaded either one to equal the other the recoil would be roughly the same. Using your data. What the anecdotal evidence does is compare apples and apples. Beware statistical evidence, remember? Lies, Damn lies and statistics.
What that does not take into account is a specific power factor that you are trying to achieve.
Anecdotal evidence sometimes doesn't match statistics. I'm not saying that what you guys are feeling is not real, and "felt recoil" is not really something that can be measured. But here are recoil calculations from an online calculator. I'm not a pistol reloader, so I don't know if I picked a reasonable load. Hodgdon longshot powder for both loads. Recoil impulse, velocity and energy higher for the 147 grain load.
In shotguns, recoil is determined mainly by the mass of the ejecta, and powder charge and velocities have a much smaller effect.
View attachment 57640 View attachment 57641
Buy a heavier gun.So 115 recoils less
Nope. The difference between 115gr and 147gr at 130 power factor is huge.So they are pretty much the same in felt recoil
Buy a heavier gun.
For most of us, who don't reload, these would be obvious choices:
Blazer CCI 9mm 147 gr 985 fps, power factor = 144.79
Blazer CCI 9mm 115 gr 1125 fps, power factor = 129.38
Recoil would have to be lower on the 115 grain.
147 gr with power factor of 130 is 900 fps. Why not load 115 gr at 900-1000 fps and get the lower recoil?
Pretty sure 115gr at 900 wouldn't run most guns anyways.
I found a 147 gr load, 4 gr powder, 883 fps. Power factor 129.80. Would that load cycle most slides?
It takes 5 gr at 1127 fps to reach power factor 129.60 for 115 grain. "Calculated" recoil is almost identical, slightly lower for the 147 gr. But I'd bet the muzzle blast and felt recoil would be lower with the heavier bullet going that slow. If it would cycle the slide.
I shoot factory 9mm 115 gr that ranges around 136-138 power factor. That's 940 fps for 147 gr. I guess I'm going to pull my dad's reloading stuff out and load some 147 grain to that speed and see for myself. He's probably too feeble to help me, other than to supervise but he used to load pistol and rifle loads.