PF safety margin for an IDPA load [Archive] - Glock Talk

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Wash-ar15
07-31-2010, 21:48
Got to chrono a load of solo 1000 and 147gr PD FMJ @ 1.14 today. out of the 10 rounds the high/low was 844/894 for 869. 844 is just below the PF while the average would be at 127. this was done on a 65 degree day.

With the 869 average,should i be concerned about not making Pf since it so close to the borderline? should i bump it up the 4.0,which is the next cavity in the Lee disk?

MSgt Dotson
07-31-2010, 22:27
127 PF is pushing it for powders with a +/-25 fps variation....; if your load were to be chrono'd for a match for which you traveled 3 hours to get to, you'd be mighty upset when it gives 124,990 (they don't round up!) if they happen to choose a handful of your weakest batch, simply thru bad luck....

dsmw5142
07-31-2010, 23:36
You could probably shorten your OAL and give it a bit of a bump. I had some 180gr .40's loaded the other day that were @1.140 and I shortened them to 1.125 and it bumped me from 164-165PF up to 169-170PF.

I would probably bump up the charge a bit though. Solo is reverse temperature sensitive. On a bit warmer day, you'd be hosed. Why take the chance? I really can't tell much difference between a 125 and a 135PF load in my G34.

Hoser
08-01-2010, 08:46
I load to either a 130 pf or a 165 pf, if the accuracy is there.

Colorado4Wheel
08-01-2010, 08:55
130 Pf. At that PF none of them should be below PF. One complete disc size may be too much extra powder. I load Solo1000 down to 1.080 with my 155gr lead. Also, the spread should shrink when you bump the pressure with that powder.

ron59
08-01-2010, 09:22
I agree with your "target" PF being 130PF... that gives you plenty of leeway when it comes time to test your ammo at a match.

I have also used Solo-1000 under a 147gr bullet. At ~125PF the rounds were VERY inaccurate. At 130PF... pretty dang good IMHO. Those heavier bullets need some "zing" to them for accuracy.

shotgunred
08-01-2010, 09:39
How often do they choreographed at your club? Mine only does once a year. I switched over to 9mm this year for IDPA to save a little money. I asked everyone what they shot with and loaded some of them up. Guess what that round didn't make PF. :whistling: So if I liked a round and it was border line I might just leave it there if I was using a lee disk. But if you get choreographed all the time it might be worth it to go up one size hole. did you raise the muzzle of the gun to move the powder charge to the rear of the case as suggested in the IDPA rule book?

IDPA Rule book
Chronograph three (3) rounds at a distance of ten (10) feet using a
gun of MAXIMUM barrel length for the DIVISION of the same
gun type. If two (2) of the three (3) rounds exceed the power floor,
the competitor is in compliance. Prior to each shot, the muzzle of
the gun should be elevated to move the powder charge to the rear
of the case, thus giving the competitor every chance to achieve
maximum velocity.

Wash-ar15
08-01-2010, 09:58
I need something for the State Championship. They will Chrono for sure.

I was looking at some other info sources. I may have gotten a slower lot of powder. My 3.7 gr load,which is commonly listed,seems to have no problem making PF according to what others have stated on the net.

shotgunred
08-01-2010, 10:10
Solo1000 is infamous for variations from lot to lot.
Yes they will at renton.

dsmw5142
08-01-2010, 13:06
Solo1000 is infamous for variations from lot to lot.
Yes they will at renton.

Very true.

Op, at the OAL your loading at I would bump it to 4.0gr and test 20 rnds. 10 for accuracy and 10 over the chrono watching for pressure signs.

Personally I would keep the charge the same and shorten my oal down to around 1.125-1.120 and try that with another 20 as long as you have the chrono out. See which makes you happy.

4.0gr of Solo with a 147gr bullet is alot of powder though and might be getting close to a compressed load, which isn't always a reason to not use it. Personally, I get the results I want with 3.5gr Solo and 147gr BBI.

As already noted though, the lots of Solo vary widely at times. Make sure you start the process over again when you get a new jug.