Finally finished my wildcat rifle project!

[Rob]

I have done a little more testing. Overall my assessment is, this is going to take some time to REALLY get dialed in with the velocities and accuracy desired. Not throwing in the towel by any means, but clearly I have not found the magic load for this rifle. I am sure part of this is "shooter" related.

First the bad news:

Max velocity I can get out of H4831SC before I hit dangerous pressures is about 3,080 FPS. This is with 55 grains of powder. I thought I could use 56 grains based on early testing. This was getting me ~3120 FPS with some cratering starting to form. Today however I had a primer Perforation which tells me this is too much pressure. Before I knew this, I tried 57 and 58 grains of powder last weekend. The craters with 57 grains were pretty significant, and at 58 grains the primer failed and was perforated. Incidentally, I was able to get 3230 FPS with 58 grains. Based on this testing, I think the max load I can safely use would be 54.5 or so grains. I estimate that would give me about 3050 FPS at the muzzle.

My buddy suggested trying RL22 as an alternate. This has some more promise.
I loaded up 20 rounds – 4 each with 52, 53, 54, 55 and 56 grains of powder. I was getting better velocities with lighter loads. 52 grains got me 3109, and 53 got me 3173. There was some cratering with the 53 grain loads, and significant craters with 54 (at 3215 fps) – I got one primer perforation out of the 4 shots fired too.  I stopped at 54 grains.

While my data does not show it, the groups with the RL22 are actually a little better. In both cases, in a 4 shot group, I had 3 of the shots under ½ of an inch, with a flier that made the group bump to just under an inch. Grr. I think that is shooter issues.

I did one more little test with the 54 grain loads today. With a 100 yard zero dialed in, I took a 300 yard 3 shot group. The group was about 8.5 inches low at 300 yards, which incidentally is pretty much what the ballistic tables say a 140 grain VLD Berger should be doing at 3200 fps.

[bobcat]

Maybe it needs an even slower powder like H1000 or IMR 7828?

[BOWHUNTER45]

that could be a good move and also I never load even numbers,, try something like 55.7 or 56.3 grains ..something in that form ...I always seem to get better groups doing that ....even 56.1 can make a huge difference ...just depends on what your gun likes !!

[bobcat]

that could be a good move and also I never load even numbers,, try something like 55.7 or 56.3 grains ..something in that form ...I always seem to get better groups doing that ....even 56.1 can make a huge difference ...just depends on what your gun likes !!

Now THAT'S something I've never heard of!  Only odd numbers huh?

Hey, whatever gives you more confidence I guess.

[high country]

Rob, if you are not familiar with ladder testing, look it up. That is where I would start. Once you get the node figured out, fiddle with seating and you ahold be close. I would go .3gr steps on the ladder.

[Rob]

High country,

Any chance you were at Kenmore yesterday?  I was talking to someone about ladder testing yesterday at the range.

[high country]

No sir....I rarely get on that side of the great divide......but hopefully it inspired you.

[Curly]

You may want to try Hodgdon's SUPERFORMANCE powder.  They made is specifically for short mags and I know that in the 300WSM people are getting their best velocities with that powder.