Powder speed and recoil characteristics

[Candiru]

I'm a new reloader who has been looking into a nice, versatile starting powder suitable for reloading several major calibers (9mm and .45ACP to start). I've shot a fairly wide variety of factory ammunition, which has led me to suspect that the type of powder used makes a big difference in the recoil characteristics.

For instance, Speer Lawman 9mm ammo has a very snappy, fast recoil, but despite this seems to have more trouble cycling stiff slides than other brands, such as Winchester white box. My guess is that Speer uses a small amount of fast-burning powder, which accounts for the snappy ignition and occasionally insufficient follow-through. This suspicion appears to be bourne out by my reloading manual. Taking Bullseye and Unique as examples, Unique almost universally produces much faster loads (especially with heavier bullet), albeit at the cost of a little more powder. This suggests to me that the burn process takes more time, providing more push but less snap. (For those who are interested, Alliant's website claims Unique burns about 60% as fast as Bullseye.)

Am I on base to assume that slower powder translates into less snappy recoil?

 

[Father Knows Best]

In a word, no. While differing burn rates of different nitro propellants may have some effect on recoil, it is so small in comparison to other factors that you are unlikely to be able to feel it.

Recoil is a function of the mass of the projectile, the mass of the firearm, the mass of the combustion byproducts (gases, mostly, for smokeless powders), and the velocity at which the projectile and combustion products depart the firearm. Of these factors, the projectile and firearm weight are by far the most important. If you load the same projectile with two different powders of differing burn rates, load them to the same velocities, and fire them out of the same gun, the total recoil impulse will be identical.

In fairness, I should point out that perceived recoil is also affected by the RATE at which that recoil impulse is delivered. I think you may be talking at that by your reference to "snappy" recoil. Sometimes I hear guys refer to it as the difference between a "kick" and a "shove." When talking about different smokeless propellants, however, the differences are so small as to be overwhelmed by the affects of projectile and firearms weight, projectile velocity, etc.

When you note that Speer "Lawman" ammo feels more "snappy" than WWB, what you are feeling is that extra velocity of the Speer, not the difference in burn rates.

 

[Rockstar]

Or, to be more precise, fast powder: sharper, more abrupt recoil. Slower powder: slower, less abrupt, more of a push, recoil.

 

[Doug b]

Candiru unique is probably the most versatile powder going.Be aware though of judging loads by recoil, factory ammo in particular.I read sometime back when a factory gets a load of powder in, a sample is sent to the lab,they develope a charge weight and send it to the shop floor to produce.One factor in this process is recoil impulse.There reasoning here is, if you the consumer take two different brands of the same caliber to the range and shoot both in the same gun and brand x "shoots" harder than brand y,brand X is going to be the one you buy and recommend to your friends.Cannister powders will get better velocity with less felt recoil.Time for a chrono.Welcome to reloading.

 

[Candiru]

Thanks for the info, guys. Given the input you've offered, I'm going to just stick with a canister of Bullseye for starters. Since I'm reloading 9mm for starters, I was going to begin with 115-grain bullets so that I could better judge how much "oomph" my rounds were receiving; however, the input offered on how the "feel" of handloads deviates from factory rounds makes it seem like a better idea to just go straight to 124-grain rounds.

 

[Rockstar]

Candiru, your username gives me the shivers; talk about ultimate pain! OUCH!!!

 

[HSMITH]

I feel significant differences in recoil impulse when switching between powders, the difference is there. Basically you have drawn the right conclusion, fast powders will feel more snappy and slow powders will be more of a push.

 

[JDGray]

More FPS = more recoil!