I've been doing some load development for my new varmint rifle, a Model 12 Savage LRPV in .22-250 with 9" twist. Thought some of you might find the results interesting. The targets were analyzed using SW (RSI Shooting lab) that allows me to hold the target up to the screen, click in the bullet holes, then click analyze and get all sorts of statistics about the group. After some thought I settled on the average group radius as the most useful indicator of group size for a GH rifle, and maximum spread as a good indicator of group quality. I also decided to use units of MOA so that results would be comparable at different ranges. This rifle was purchased for shooting GH out to 500 yards or so, hence the desire for being able to directly compare shooting performance at different ranges - MOA works well for this.
MS = group Max Spread in MOA. AGR = Average Group Radius in MOA. Loads
modeled in QL using the measured water grain capacity from spent brass
(55g), measured COL and library powder data.

Savage Model 12 LRPV, 100 yards, 85F, light breeze, IMR4320 + 55g V-MAX,
2.49" COL (0.20" off lands), WLR primer - powder screening test:

33.4g gave 3561 fps, MS=0.59, AGR=0.24. QL Predicts 3,350 fps (-5.9%)
33.9g gave 3617 fps, MS=0.49, AGR=0.19. QL Predicts 3,399 fps (-6.0%)
34.4g gave 3667 fps, MS=0.65, AGR=0.22. QL Predicts 3,446 fps (-6.0%)
34.9g gave 3703 fps, MS=0.49, AGR=0.23. QL Predicts 3,493 fps (-5.7%)

Savage Model 12 LRPV, 100 yards, 65F - 70F, light breeze, Load is
indicated charge weights of H380 with 55g V-MAX, Winchester brass, WLR
primer, 2.49" COL (0.20" off lands) - powder screening test:

35.5g gave 0.20 AGR, 0.23 MS @ 3448 fps. QL Predicts 3,420 fps (-0.8%)
37.5g gave 0.29 AGR, 0.79 MS @ TBD fps. QL Predicts 3,611 fps
38.0g gave 0.32 AGR, 0.67 MS @ 3684 fps. QL Predicts 3,658 fps (-0.7%)
38.5g gave 0.37 AGR, 1.04 MS @ 3738 fps. QL Predicts 3,706 fps (-0.9%)
39.0g gave 0.15 AGR, 0.45 MS @ 3764 fps. QL Predicts 3,753 fps (-0.3%)
39.5g gave 0.12 AGR, 0.29 MS @ 3790 fps. QL Predicts 3,800 fps (+0.3%)

This is pretty good agreement IMO. Within 6% for IMR4320 is good, less
than 1% for H380 is fantastically good but maybe only good for this
bullet weight in this gun. This is the first time I've done a good
documented comparison over a range of powder charges. The good
agreement had me avoid the max published load of 40.6g (Hornady manual)
for this bullet because it models as 1,600 psi over the limit. I
realize good velocity agreement doesn't mean good pressure agreement but
better safe than sorry. One of the reasons for using the SW is to help
keep this novice reloader out of trouble.

Edited to add, the above were 5 shot groups.

Fitch

Nice work, Fitch! but i'd like to see what you can do with heavier bullets with that fast twist. roger

quote:

Originally posted by bartsche:
Nice work, Fitch! but i'd like to see what you can do with heavier bullets with that fast twist. roger

You and me both. I can hardly wait to see how it does.

That is the next task. I have some 65g Sierra bullets set up for 3 shot group screening loads and I'm heading for the bench now to load up a similar set of 75g A-MAX loads. It will probably take a while and several range trips (ohboy!).

Fitch

I have this feeling that the H380 and the A-Max combination is going to set your world on fire... in an exciting way. Graet bullet and perfect combination (.22/250 w/ 1 in 9.)

For what it is worth.. IMr 4064 and IMR 4895 both proved to be the most accurate powders with 75, 77 and 80 grain bullets in my 22.250, this was compared to 15 different powders total... one in 8 twist.. Barrel is a 24 inch Pac Nor...mounted on a Ruger 77 Mk 2 action...

Hornady's 75 grain HP also proved to be more accurate than the A Max...with 15 different powders tested..

quote:

Originally posted by seafire2:
For what it is worth.. IMr 4064 and IMR 4895 both proved to be the most accurate powders with 75, 77 and 80 grain bullets in my 22.250, this was compared to 15 different powders total... one in 8 twist.. Barrel is a 24 inch Pac Nor...mounted on a Ruger 77 Mk 2 action...

Hornady's 75 grain HP also proved to be more accurate than the A Max...with 15 different powders tested..

Thanks for the heads up. 15 powders is a "bunch" of testing!

I need to get some of the IMR4895. Don't have any of that or any IMR4064. I did load some 75g A-MAX with H4350 last night - will take them to the range later this week and report back on how they do.

If the Gander between here and the range has IMR4895 in stock, I'll pick up a pound of that on the way back.

I do have a box of the 75g BTHP to try as well.

VV N550 looks really good in QL models for 75g bullets in this rifle but I don't have any of that yet. I have some N560 that I use for 100 grain bullets in the .243 but it's too slow for the .22-250.

The Hornady manual shows H414 (that I don't have) which is pretty close to W760 that I do have, so I may also try a test with W760.

Fitch

Do yourself a favor and get 8# or more of DP 85 from Powder Valley, ( If it is still available). It is a ball powder with the burning rate similar to the 4350s. Since it is ball and of the right density you can get more of it into the 22-250 case without compression and more with just a LITTLE compression.Do you have a deeper than normal throat on that rifle?

The last I remember the DP 85 was selling for around $69.00/8#. Go in with a couple buddies split the HAZMAT and get 6 jugs. roger

WELL WORTH IT!!!!

quote:

Originally posted by bartsche:
Do yourself a favor and get 8# or more of DP 85 from Powder Valley, ( If it is still available). It is a ball powder with the burning rate similar to the 4350s. Since it is ball and of the right density you can get more of it into the 22-250 case without compression and more with just a LITTLE compression.Do you have a deeper than normal throat on that rifle?

I don't think it has a deeper than normal throat but I haven't measured it either. I am loading .020" off the lands. The base to where the lands contact the Ogive is something like 2.113" if I'm doing it right.

I'll look into DP 85. What I'd really like is some VV N550 to experiment with for heavy bullets in the .22-250. N550, in fact most of the "N5xx" VV powders look like they get up to pressure as fast as the conventional powders plus, if the profile on QL is correct, they have a noticably slower pressure decay than other powders. The net effect, near as I can tell, is a higher average pressure for a given peak pressure. That should, if it happens in the rifle, yield a bit more MV for the same peak pressure, which if it also shoots well, would be a good long range load.

It's all in the shooting, but it doesn't hurt to do a little head scratching before reaching for the bullet box either.

I wonder if anybody has tried N550 with heavy bullets in a .22-250 Rem. cartridge and has some data?

Fitch