Can you feel a PF difference of 5?

[JAFO]

I've chrono'd 10 rounds of my current load (124gr FMJ 9mm/6.7gr HS-6) just to make sure I was making Minor, and I'm currently averaging ~141 PF. I realize that 10 rounds is a small sample size and I'll do more when I have access to a chrono again (hopefully my own after Dec 25 ). I'm wondering, assuming my average is correct, if it's worth it for me to try to reduce it down to ~135 PF. Can you really feel a difference between ~1140 fps and ~1090 fps?

Or am I going about this wrong? This is the only load I've ever used and I'll own up to the fact that I don't know how well it groups from my 226. What criteria do you use to decide when to settle with a load?

Thanks!

[Graham Smith]

I have not used that powder, but you might want to check to see if there are any issues with temperature sensitivity. If so, you might want to make allowance for that.

Normally, a 135 PF is high enough to keep you out of trouble, but it's more about how well your gun does than anything. Most are fine with 125 but some don't do well that low.

You want to find a load that gives you good consistency and cycles your gun well. You might want to search to find Matt Burketts timing drills. These are great for finding out just what your gun is doing.

[CocoBolo]

You normally won't notice a +-5 pf change.

HS6 is an open gun powder so being +-5 pf really shouldn't make any difference. In the future you might want to consider than in non-compensated pistols the theory is that a faster powder with a heavier bullet is preferred.

The P226 is known for more that normal muzzle rise since the Axis of the Bore line is higher above the grip than most. That said its a flipper.

I settle on a load when I have tested all the players in the correct ball park and made my decision based on field testing. So in the case of the P226 this would include 115gr, 125gr and 147gr bullets with TiteGroup, N320, WST, Solo 1000 and any other powder in close speed range just listed.

[lcs]

I think you need to move up the powder chain also. HS6 is rather slow burning. Great 9 Major powder, not so great for 9 minor rounds. To answer your question on feeling a 5 PF differnece? I would not think so at 135 to 140 range.

[bbbean]

IF I am 100% focused on recoil, I can tell that there was *a difference* in two rounds with a 5 pf difference at major pf levels. But if I am focused on sights, movement, target, etc (i.e. actually shooting), then no. My own chrono runs show that in a 20 round run, I'll have a sd of 2-3, and a spread of 6 or 7 pf from high to low, but they all feel the same in practice or at the match.

Most minor shooters opt to allow a comfortable margin of error between what their chrono says they're running at, and what the natch chrono might say. Nobody wants to go sub-minor and shoot a match for no score.

If you're currently running 141, you're not leaving a lot of room for error if you run across a "slow" chrono. Personally, I'd think about bumping it up to 145.

Sorry - I had minor=135 stuck in my head. If you're at 141 you should be pretty safe for minor.

Edited November 23, 2010 by bbbean

[G-ManBart]

Generally speaking, I don't think most people (if anybody) can tell a difference of 5PF. With your 124gr bullet, that works out to be 41fps. Most loads will have an extreme spread somewhere in that ballpark. I've played around with this on the chrono, trying to see if I could call whether a shot was higher, or lower, in velocity, and I can't do it with any consistency.

HS-6 is pretty slow for a Minor load, so you may want to consider something faster (for softer feel). If you're in the 135-140PF range, you're in a very safe place. My current 9 Minor load averages 137-138PF, but I wouldn't change if it was a touch higher...any lower, and I would. R,

[G-ManBart]

IF I am 100% focused on recoil, I can tell that there was *a difference* in two rounds with a 5 pf difference at major pf levels. But if I am focused on sights, movement, target, etc (i.e. actually shooting), then no. My own chrono runs show that in a 20 round run, I'll have a sd of 2-3, and a spread of 6 or 7 pf from high to low, but they all feel the same in practice or at the match.

Something about that math doesn't work out. If you managed to get an SD of 2-3 (which is almost unheard of), the ES would be nowhere near 6-7PF. With a 124gr bullet (like the poster mentions), 6PF is 49fps. An ES of 49 would put the SD around 12 going off what I've seen (I've had plenty of loads with an ES in the 40s and SDs of 10-12). R,

[JAFO]

Well, I guess that's what I get for taking my first powder suggestion from a 9mm Major Open shooter.

I'll look into one of the other powders mentioned here and go from there.

I'd think a faster powder would give a sharper recoil impulse than a slower one. Why do faster powders result in a softer feel?

[usmc1974]

I've chrono'd 10 rounds of my current load (124gr FMJ 9mm/6.7gr HS-6) just to make sure I was making Minor, and I'm currently averaging ~141 PF. I realize that 10 rounds is a small sample size and I'll do more when I have access to a chrono again (hopefully my own after Dec 25 ). I'm wondering, assuming my average is correct, if it's worth it for me to try to reduce it down to ~135 PF. Can you really feel a difference between ~1140 fps and ~1090 fps?

Thanks!

I say No,

[bbbean]

IF I am 100% focused on recoil, I can tell that there was *a difference* in two rounds with a 5 pf difference at major pf levels. But if I am focused on sights, movement, target, etc (i.e. actually shooting), then no. My own chrono runs show that in a 20 round run, I'll have a sd of 2-3, and a spread of 6 or 7 pf from high to low, but they all feel the same in practice or at the match.

Something about that math doesn't work out. If you managed to get an SD of 2-3 (which is almost unheard of), the ES would be nowhere near 6-7PF. With a 124gr bullet (like the poster mentions), 6PF is 49fps. An ES of 49 would put the SD around 12 going off what I've seen (I've had plenty of loads with an ES in the 40s and SDs of 10-12). R,

Note that I'm talking major, not minor, and I'm talking sd of pf, not of fps. I have my .45 SSN notes handy: 20 rds, high pf= 177.35, low pf=170.17, sd=2.15. I was worried about going minor and got carried away. I went 178 at the match chrono.

[al503]

I remember a thread a while back on this and I specifically loaded some test ammo for a new limited pistol (9mm) to see if I could tell the difference. The difference is not night and day but it was very noticeable when shot side by side.

[Sean Gaines]

I can feel the difference between brass and nickle cases. Nickle feeds and shoots smoother than brass, that was in my open gun though. I remember a thread about it along time ago, about nickle feeling softer. and I would have to agree.

[Shadowrider]

It depends. I can discern some difference in my plastic fantastics. But in the 1911/2011 platform? Not so much.

[Seth]

I've done Chrono for the VA/MD Section match a couple of times. Figure that's around 200 guns I personally shot over the weekend. 1200ish rounds over the 2 matches. By Sunday AM I could guess pretty accurately where pf was within about 7. It was a dumb game I played to keep from going nuts....

MY answer is if the load is accurate at 140, see if its accurate at 130. You CAN tell a difference. But to 135? Nah. Waste of powder.

Edited November 24, 2010 by Seth

[G-ManBart]

Note that I'm talking major, not minor, and I'm talking sd of pf, not of fps. I have my .45 SSN notes handy: 20 rds, high pf= 177.35, low pf=170.17, sd=2.15. I was worried about going minor and got carried away. I went 178 at the match chrono.

Ah, I've just never seen anybody describe SD and ES in terms of PF...gotcha. R,

[G-ManBart]

I'd think a faster powder would give a sharper recoil impulse than a slower one. Why do faster powders result in a softer feel?

Nope, works the other way around. The faster powder gets the impulse over quicker, the charge weight of the powder gets added to the bullet weight, for recoil purposes, so smaller charges are better, and the volume of gas going out the end of the barrel has a jet effect back into your hand...so less powder means less gas volume, which means less jet effect. R,

[usmc1974]

Damm guys, if you can tell the difference, between, 1140 fps and ~1090 fps with a 9mm 124 grainer you are Good.

[JorDanO]

I could tell a huge difference when I switched from Autocomp to Solo 1000 for my minor loads. According to Hodgdon, Autocomp and HS-6 are pretty close in their burn rates. At the same PF Solo was way softer.

[G-ManBart]

I could tell a huge difference when I switched from Autocomp to Solo 1000 for my minor loads. According to Hodgdon, Autocomp and HS-6 are pretty close in their burn rates. At the same PF Solo was way softer.

Well, according to the chart, they should feel quite a bit different. Solo 1K is #16 and AC is #43...big gap there.

Keep in mind that burn rate charts are limited in their utility...and none of them entirely agree. They only show what the burn rate is in open air, not when confined within a case...the two can be significantly different. That's why two powders that are close to one another on the chart can have big differences in feel and max charge weights. R,

[Sean Gaines]

"Keep in mind that burn rate charts are limited in their utility...and none of them entirely agree. They only show what the burn rate is in open air, not when confined within a case...the two can be significantly different. "

that is interesting! I guess you learn something new everyday

Edited November 27, 2010 by Sean Gaines

[G-ManBart]

"Keep in mind that burn rate charts are limited in their utility...and none of them entirely agree. They only show what the burn rate is in open air, not when confined within a case...the two can be significantly different. "

that is interesting! I guess you learn something new everyday

Yeah, it is pretty interesting/odd. The other thing is sort of a wild card....with some powders the lot to lot variation is pretty significant. We'll never know what lot they actually tested, so it's one more variable, and probably a big part of why we should always start 10% lower, and work up. R,

[JAFO]

Less gas = less felt recoil makes sense. I'll be ordering some Titegroup as soon as some friends decide what they want from Powder Valley.

If I may ask, how do you guys work up your loads? Do you test and adjust the load for accuracy first and then chrono for velocity, using whatever PF you get (assuming ~135 or more)? Or do you check velocity and adjust the load to meet your desired PF, then go +/- 0.1 or 0.2 or 0.3 gr while checking accuracy? I figure if I'm going switch powders, I might as well do a more thorough job of working up the load this time.

[MoNsTeR]

If and only if everything else is constant, and the loads are consistent enough (in terms of SD) that the distributions don't have massive overlap, I can tell the difference. Here I'm thinking of my own N310 minor load where I get SDs of about 7-9fps and going up or down a tenth is all it takes to change the PF by 5(-ish). But, that should not be taken as a recommendation to chase a target PF as if it were a magical number. If you have a load you like and that comfortably makes minor, stop messing with it and start shooting it.

However, as other posters have done, I would endorse using a (much) faster powder than HS-6.

[G-ManBart]

Less gas = less felt recoil makes sense. I'll be ordering some Titegroup as soon as some friends decide what they want from Powder Valley.

If I may ask, how do you guys work up your loads? Do you test and adjust the load for accuracy first and then chrono for velocity, using whatever PF you get (assuming ~135 or more)? Or do you check velocity and adjust the load to meet your desired PF, then go +/- 0.1 or 0.2 or 0.3 gr while checking accuracy? I figure if I'm going switch powders, I might as well do a more thorough job of working up the load this time.

Get the PF in the ballpark of what you want, see if it's accurate. If it is, load a bunch of it! If it's not, tweak it as necessary. Most times, loads within the range we want are going to be accurate enough for what we do. R,

[Sean Gaines]

"Keep in mind that burn rate charts are limited in their utility...and none of them entirely agree. They only show what the burn rate is in open air, not when confined within a case...the two can be significantly different. "

that is interesting! I guess you learn something new everyday

Yeah, it is pretty interesting/odd. The other thing is sort of a wild card....with some powders the lot to lot variation is pretty significant. We'll never know what lot they actually tested, so it's one more variable, and probably a big part of why we should always start 10% lower, and work up. R,

I knew there were variations lot to lot, what interesting to me is the fact that there is so many variables when comming up with a load that it will make your head spin, unless you don't care and you just make a load and shoot it.

variables:

burn rate

seating depth

pressure

bullet

bullet weight

profile

primers

gun

weight of gun

weight of slide

gun fit

springs (multiple springs)

barrel

barrel twist

compensator

gas

weather

etc, etc

than you have to find one that shoots accurate in your gun, and feels good in your hands. manipulating one of these variables, and then you could have a different impulse or feel. I am sure someone could come up with some in depth equation to figure out what you want with plug in variables. but the problem is finding all the variables. talk about a mathmatician's nightmare...

the same exact load in one gun, will feel different in another