Relationship between PF and felt recoil

[bbbean]

I've always assumed that two loads of a similar power factor should have a similar level of recoil, but never tested that theory. Today, however, I ran out of my own loads (3.7 clays, 230 gr Precision Bullet, PF=166) and loaded my mags with Atlanta Arms 230 FMJ (PF=167). I've never thought of AA ammo as heavy recoiling, but compared to my own load, if felt like I'd gone to a self defense (PF=180+) load. For grins, I also tried a box of AA 185 JHP (PF-174). The two Atlanta Arms loads felt very similar, with the 185 being a little snappier, but both felt dramatically different from my Clays/moly 230 load.

I know that at least part of the perceived difference is that the AA powder has a very different sound than Clays - it is much deeper and throatier, so that may explain part of the difference.

But I'm also wondering if a bigger part of the difference is that moly is faster than jacketed ammo, so I'm using less powder to achieve the same velocity. On the other hand, if this were the case - that the faster the bullet, the lighter the perceived recoil, wouldn't everyone be using greased lead?

Am I missing something?

[GrumpyOne]

I would think the powder has more to with it than what you are suggesting. The bullet does have it's part in recoil, but whether you are using a slower or faster powder also has it's place in recoil. From what I understand (I don't use Clays), Clays is a pretty fast powder, so loading a bullet with a similar speed powder should match the recoil to your Clays load. AA may use a slower powder, which would have a big difference in percieved recoil. I'm no expert in the speeds of powders and their relantionships with recoil, but from what I see on the forum, open shooters (like me) prefer slower powders (light bullet moving fast, with lots of gas), while production, limited, etc. prefer faster powders (heavy bullet moving slow).

[ben b.]

Did you chrono the rounds, so that you KNOW both 230 loads are the same PF?

I have found wide variance from box listed velocities, in both directions.

[Jman]

A link to some fine reference material about recoil. Might be of some help.

http://www.mattburkett.com/pdf/tipsandarticles.pdf

Jim

[bbbean]

Did you chrono the rounds, so that you KNOW both 230 loads are the same PF?

Yes. Back to back, same gun, same chrono, same day. 24 rounds of each.

[bbbean]

Let me simplify my question. My current load makes 165 pf at 70 degrees with a moly 230 bullet and 3.7 gr of Clays. If I work up a load using Clays and a Montana Gold 230 FMJ, I'll need somewhere around 4-4.1 grains of Clays to make the same power factor. Would you expect the two loads to have similar felt recoil?

FWIW, I know I could just work up the FMJ load, but if someone else has done this, I can avoid the time and trouble of working up a load I may or may not use when my press is already set up to run a pretty nice load.

[ben b.]

Let me simplify my question. My current load makes 165 pf at 70 degrees with a moly 230 bullet and 3.7 gr of Clays. If I work up a load using Clays and a Montana Gold 230 FMJ, I'll need somewhere around 4-4.1 grains of Clays to make the same power factor. Would you expect the two loads to have similar felt recoil?...

No, I would not. When you burn more go-juice, that energy goes somewhere, and it isn't all lost in the friction of pushing those hard-assed MG pills down the pipe.

[CocoBolo]

I only use Precison Moly in my 45 200gr w/4.3gr of clays. Shoots like an airsoft. Now in 40 I have used a variety of bullets and in a limited gun less of the same powder and a heavier bullet works to soften things up. In a 40 4.7gr WST behind a moly is a lot softer than 5.1gr behind a jacketed bullet both at 171pf, and its that extra gas and bang that does it..

Could I suggest that if you cannot get precision bullets try http://www.bayouBullets.net. These are clean bullets, and I mean nothing on the hands and nothing in the tube. The precisons are not nearly as clean and maybe its time you quit smoking. I shot some in my open gun today at 1360 fps they shot well and no goop in the comp or barrel. I can't do that with the moly they tumble, fly sideways and crap all over the gun. Then its chore boy and dentist pick time cleaning.

I don't know what the green stuff is they joke and call it gator snot.

Edited April 4, 2010 by CocoBolo

[njl]

I've read conflicting things on this. What it boils down to is:

To send the same weight bullet downrange (from the same gun) at the same velocity, you're going to have the same amount of recoil.

Faster powders have less perceived recoil.

Clays being a really fast powder, should feel softer shooting at the same velocity as a slower powder.

I'll find out first hand soon...as I started out with Universal Clays, and am about to give Clays a try.

[CocoBolo]

I've read conflicting things on this. What it boils down to is:

To send the same weight bullet downrange (from the same gun) at the same velocity, you're going to have the same amount of recoil.

Faster powders have less perceived recoil.

Clays being a really fast powder, should feel softer shooting at the same velocity as a slower powder.

I'll find out first hand soon...as I started out with Universal Clays, and am about to give Clays a try.

I takes more powder to push a Jacketed bullet at the same speed = more recoil. I don't think you can beat Clays in a 45 for Soft. I've tried a bunch of powders N320, WST, 231 to name some of the better ones. I shoot 200gr in 45 because you get more of a limited gun feel I'm sure a 230gr would be even softer, but I'm running a 12# recoil spring as it is.

[superdude]

all else being equal (bullet weight, velocity), gunpowder is the largest component behind differences in felt recoil. for a more detailed explanation see:

http://www.38super.net/Pages/Recoil.html

[Justsomeguy]

Let me simplify my question. My current load makes 165 pf at 70 degrees with a moly 230 bullet and 3.7 gr of Clays. If I work up a load using Clays and a Montana Gold 230 FMJ, I'll need somewhere around 4-4.1 grains of Clays to make the same power factor. Would you expect the two loads to have similar felt recoil?...

No, I would not. When you burn more go-juice, that energy goes somewhere, and it isn't all lost in the friction of pushing those hard-assed MG pills down the pipe.

I'm with Ben on this. Energy is energy! The more you burn, the more you feel. More powder = more recoil. That is... more of the same powder will make more recoil. Fast powders do it quicker so it's not perceived as readily. Slower powders push a bit slower over a slightly longer period of time, but the total energy released is what counts in my opinion.

As to bullet weight... A heavy bullet for the caliber uses less powder to make power factor, thus less recoil for the particular power factor. Open gun shooters use light bullets at high velocities (using MORE powder and energy), but vent the gasses into a compensator to lessen the recoil while producing more energy.

[Graham Smith]

As I understand it, a really fast powder that expends most of it's energy early on will have less perceived recoil than a powder that may not finish burning till the bullet is well down the barrel.

Also, 167 PF Major ammo seems low for AA. IIRC, they usually give you bit more than that so you will safely pass the chrono.