does burn rate of powder effect felt recoil?

[dgang]

A question to those who might know: If I were to load a cartridge with say a 158 gr. .357 dia.bullet with a fast burning powder like Bullseye to produce 1000 fps, would the felt recoil be the same as , less than, or greater than that same cartridge loaded with a slow burning powder like 2400? Same bullet @ the same velocity, Same recoil?
Thanks in advance, dang

 

[WestKentucky]

It's a function of moving mass, so unless your loading the same weight of powder and getting the same speed with the same bullets you will have different recoil...but what you feel is not really what changes recoil usually. Flash and noise affect perceived recoil as much as actual recoil.

 

[Crunchy Frog]

In general burn rate is one of the factors affecting felt recoil but its not the only factor. A friend uses Titegroup and I use Red Dot, a powder with a similar burn rate, in our .38 Special cowboy action loads. I find Titegroup to produce snappier recoil and a sharper report.

In general, though, I think a slower burning powder would produce less felt recoil than a faster powder pushing the same bullet at the same veloicity.

 

[JeffG]

Olin 296 was always a softer recoil in magnums, with heavier bullets;in as much as recoil spread over an almost imperceptible time dwell. But the bullet weight increase would push the barrel up a little more. Faster powders seem to smack the hand a little more.

 

[dgod]

Recoil is determined by several factors: Firearm Weight, Bullet Weight, Bullet velocity, etc. Here is a link to the SAAMI formula:

http://www.saami.org/PubResources/GunRecoilFormulae.pdf

In other words, same weapon, same Bullet & Weight, Same Velocity, = Same Recoil.

 

[wally]

Faster powders seem to smack the hand a little more.

So you are claiming you can "feel" the difference in something where "fast" and "slow" differ by a few tens of microseconds?

Here is a recoil calculator:
http://www.handloads.com/calc/recoil.asp
Generally for handguns the powder charge has a fairly small impact simply because the charge mass is small compared to the bullet mass, but the escaping gases have much higher velocity so the effect is not totally negligible.

Plugging in the numbers for a 230gr bullet at 850 fps with two mythical powders that produce the same velocity with charges of 5.0gr and 7.8 gr for the other. The 5.0 grain load has a recoil impulse of 0.96 lb-sec while the 7.8 gr load is 1.01 lb-sec

Doing the same for 124 gr bullet at 1100 fps and powder charges of 5gr and 10gr the recoil impulses are 0.69 lb-sec for the 5gr and 0.78 lb-sec for the 10gr load.

I'm of the opinion than most of the perceived recoil differences other than these maybe 5-10% changes in recoil impulse is mostly your reaction to the muzzle blast and flash from the "uncorking" pressure.

The recoil impulse is the "thrust" imparted to the firearm from the shot. Its independent of the weight of the gun and how you grip it.

 

[Blue68f100]

In general terms. I find that slower burn powders produce more of a push type recoil. Where the faster burn powder is snappier.

 

[Jonesy814]

If one load used more powder it would also create more recoil but that doesn't mean you could actually feel the difference

 

[JeffG]

So you are claiming you can "feel" the difference in something where "fast" and "slow" differ by a few tens of microseconds?

Here is a recoil calculator:
http://www.handloads.com/calc/recoil.asp
Generally for handguns the powder charge has a fairly small impact simply because the charge mass is small compared to the bullet mass, but the escaping gases have much higher velocity so the effect is not totally negligible.

Plugging in the numbers for a 230gr bullet at 850 fps with two mythical powders that produce the same velocity with charges of 5.0gr and 7.8 gr for the other. The 5.0 grain load has a recoil impulse of 0.96 lb-sec while the 7.8 gr load is 1.01 lb-sec

Doing the same for 124 gr bullet at 1100 fps and powder charges of 5gr and 10gr the recoil impulses are 0.69 lb-sec for the 5gr and 0.78 lb-sec for the 10gr load.

I'm of the opinion than most of the perceived recoil differences other than these maybe 5-10% changes in recoil impulse is mostly your reaction to the muzzle blast and flash from the "uncorking" pressure.

The recoil impulse is the "thrust" imparted to the firearm from the shot. Its independent of the weight of the gun and how you grip it.

Yes. Granted it is subjective. I had a MAC10 full auto in 45acp. By changing powders and burn rates, it was possible to change the cyclic rate of the gun, and hear the difference also. How it felt in the hand was noticeable also.
With magnum pistols the feel between a push recoil that is spread out over a millisecond more time, is more comfortable than a faster "hotter" load that feels like hitting your hand with a fish billy. Slower powders have a slower time/pressure/dwell curve than faster burning powders.

 

[Walkalong]

Yes it can, but there are other factors obviously.

A top .357 load with N340 vs a top load with 2400 and the 2400 load will feel less sharp.

 

[Reloadron]

Just keep in mind the difference between FRE (Free Recoil Energy) and what we call "Felt Recoil" with felt recoil differing shooter to shooter with the same gun and load. SAAMI provides the formula and actually Hatcher's Notebook has a very good section discussing FRE.

Something else which is interesting and humorous is there are a number of online recoil calculators. Try a few and don't be surprised if you place the same exact data in a few and get slightly differing numbers back.

Ron

 

[wally]

Something else which is interesting and humorous is there are a number of online recoil calculators. Try a few and don't be surprised if you place the same exact data in a few and get slightly differing numbers back.

There are a lot of assumptions when trying to add in the contribution from the powder gases. I'd wager the ones based on the SAMMI formulas are probably the best place to start, but the one I linked didn't specifically mention what equations they are using (or its not obvious at the top level page).

Yes. Granted it is subjective. I had a MAC10 full auto in 45acp. By changing powders and burn rates, it was possible to change the cyclic rate of the gun, and hear the difference also

MAC 10 is a blow-back design, odds are its the residual pressure making the difference more than the "speed" of the powder. The rate of the bolt going forward is largely set by the recoil spring and bolt mass with a bit of influence from the magazine spring. If your loads are increasing the bolt velocity going back you are over loading it. I have a Thompson SMG, I keep my loads as close to "GI" 230gr 850fps as possible given its value, I want as long a life as possible. I've replaced the recoil spring and fiber buffer many times.