[Dragon21]

How close to power factor do you try and load? I took my 9mm to the range today and chronoed it. to get power factor @115 grain i need 1087fps, i was chronoing about 1115-1140 (not as consistant as id like). Factory rounds are about 1260-1270. Should i keep the load i have, or try to get closer to power factor?

 

[NCCruffler]

I used to be dog nuts about velocity and the all important power factor.
Now I go with the load that is the most consistant and accurate for the weapon I am using.
Have you ever heard a target exclaim how powerful a bullet was...as it passed by without making a hit?

 

[Dragon21]

Sometimes I hear the steel laugh at me. I completely understand what your saying. Trying to find a combination of both accuracy and power factor.

 

[SkydivnShooter]

While getting ready for the NC Sectional last year, I chrono'd Caleb's minor (125pf) loads at 128.5 pf running a 147 CMJ MG at 874 fps. I didn't feel real comfortable at 3.5 over the pf so I tweaked the load to get to 132.3 pf - same bullet travelling right at 900 fps.

All that work and time turned out to be a waste as the MD waived the chrono stage on Friday and no one had to go through it for the entire match.

I run my major (165pf) load - 180 gr CMJ MG at 169 - 173

 

[laxdadoo]

I would go a little hotter, that's just too close. a different chronograph or just temperature changes could throw you lower than minor. Aim for a power factor that's about 10 above. Again it must be accurate. And don't be afraid to try different bullet weights

 

[sleipnir]

I loaded up several hundred rounds of my then favorite load and went off to the SC Section match. I made major by about .01 fps. Sweated bullets that trip to the chrono. I took the same ammunition to Washington State's Section match and chrono'd a power factor of 210. The match director almost decided that the ammo was unsafe. Same load, different time, place and chronograph. I don't know what lesson I learned from that.

Anyway I try to load for five points above the floor. (e.g. for 165 I load to 170) That's worked well (except in the above situation) over the years.

But, as said earlier, accuracy is king.

 

[Dragon21]

thanks guys, i think im gonna try bringing it down a few grains and see where i end up. cant try differnt weights right now beause i have about 950 bullets left. haha. and with my lee auto measure, the disks only let me move in .3 incriments. but even the load i just shot, was noticibly softer then factory ammo, didnt do any accuracy shooting though, just over the chrono with those.

 

[laxdadoo]

If you bring it down a few grains you won't be making power factor. PF for minor is 125 your load works out to be 128 how low you want to go. It does not make a big difference in recoil.

 

[Dragon21]

Wasn't sure how each grain equals to fps. Was thinkin trying for about 1100 fps. I guess with info that's been provided. maybe I should leave a little more room for error then that though and stick with what I have.

 

[FlatFender]

I'm no reloader, but I've read some crazy stories about temp causing rounds to do some interesting things. I wouldn't want to get that close to 125...

 

[SkydivnShooter]

Just food for thought:

During my early testing, as a control, I chrono'd WWB ammo at an average of 1173.8 fps which yields a 134 pf.

I figure, if I can't dial my load in at less than 134, why am I reloading for competition?

 

[elward]

Sorry to ask. What is power factor?

 

[SkydivnShooter]

Sorry to ask. What is power factor?

Power Factor is used by competitive governing bodies, mainly USPSA and IDPA, in the scoring formula, as a way to equal the playing field for large caliber shooters competing against 9mm shooters.

The theory is, less muzzle rise from a 9mm allows that shooter to index on the target quicker, thereby giving that shooter an advantage over say, a .45 Auto shooter.

Also, as you can tailor your gun and reloads to a minimum muzzle rise as long as the gun still operates, an established power factor minimum (125 in USPSA) helps level the playing field for all those 9mm shooters that would otherwise take advantage by say, building a gun and round that would fire a 9mm bullet with a .22lr. recoil.

It is calculated by:
Bullet Weight in grains x Muzzle Velocity in feet per second / 1000 = Power Factor

example - 115 gr bullet x 1150 fps = 132,250. 132,250 / 1000 = 132 Power Factor

Hope that 'splains it.