How to improve accuracy on my loads

[HNSB]

Right now I am having some trouble getting my boolits to shoot well out of my 357 (Ruger Blackhawk).

I have loaded cast in 9mm, 45 ACP, and 40 SW in the past with good success. This is my first attempt at a magnum cartridge, as well as a wheelgun, and GC'd boolits...

The boolits dropped from the mold fine. They are all consistent for weight and hardness. I size them all on a lee 358 push through. I don't think the boolits are the problem.

The boolits after being sized push through the chamber throats with a little finger pressure. The bore is slightly smaller than the throats. From everything I've read, that is ideal for a wheelgun.

But... I put together several test loads of 2400 over SP primers. The best group I got was 4" at 20 yards, shooting off a rest.

I am planning on trying some loads with SPM primers, as well as some other powders. I just wanted to pick some brains though, to see if this is a matter of not having the right recipe yet, or if I am missing something.

What are the biggest factors that determine accuracy?

Also... My chrony shows these boolits going substantially faster than what the load data indicates they should. The bullets weigh in at 160 grains... My manual lists a max load using a regular SP primer as 15.3 grains of 2400. I started low and worked up. I never shot the 15.3 grain load I had made. I did not have any flattened primers or sticky cases (beyond normal for this gun) with any of the loads, but by the time I got up to 15.0 grains the chrony showed the boolit travelling at about 1630 fps (from a 4-5/8" bbl). Again, no pressure signs, but that just seemed so much faster than expected and I didn't want to take any chances.

[frank_1947]

key words you said, first time with mag and wheel gun, could you be flinching from expected noise and muzzle flip, trigger pull? wheel guns are different in magnum to shoot then 9mm 40sw and45acp you know anyone who is a good wheel man let him shoot it. 20 yards 4 inch not so good at all, I have never been good at all with wheel gun.

[Shiloh]

How does this wheelgun shoot with other boolits? Any difference in jacketed or cast??
What about commercial boolits?? Sounds like the cylinder chambers are okay.

Shiloh

[runfiverun]

back it down to 12 grs and then move along as you get more comfortable.

[mooman76]

Have you checked for leading? That will tell you allot right there. If you have no leading then that of coarse is good and indicates you have a good bullet as far as diameter and hardness. Try shooting some unsized and see if that helps. You also didn't say which bullet you are using. Some guns may shoot particular bullet better than others. WCs will generally shoot better than other bullets in pistol but of coarse that doesn't always hold true. Sound like you are using some pretty stout charges. Maybe still under max but your heavier charges usually don't produce the best possible accuracy. You could also try some other powders or lighter charges if you haven't already. We could sit here all day saying things to try but these are the first things I would work.

[looseprojectile]

always gets a magnum primer when using a casefull of powder. Start at 13.5 grains or a little less of 2400 when changing primers to magnum. Lube makes a big difference.
I have always got better accuracy with increasingly heavier charges of powder.
The faster they go the better. Within reason of course. Some I have shot were way beyond reason. Alloy/hardness can be explored. I have always used gas checked boolits for the faster loads in the .357. Hollow point boolits are always more accurate if all else is the same.
Another thing I have found is that the .357 case needs to be expanded enough to not ruin the boolit when seating. Use a good/heavy crimp with 2400.
Four inches at 60 feet is not too horrible. I find that some of my one inch groups at 25 feet become six inch groups at fifty feet. Have you tried .38 special target loads in mag. cases? With the same boolits? How's the trigger? Leading?
I shoot a S&W model 28 and if I miss it ain't the gun. I look to the ammo or my technique. Keep after it. Most Ruger single actions will shoot really good with the right load. I love em.

Life is good

[JRR]

I find that the cases and their consistency have the most influence upon accuracy. The 357 is a crimped round and the overall length of the case will affect the amount of crimp. If the cases are of mixed brands, with differing wall thickness than the crimp will be affected as well as bullet hold.

Use a case trimmer from any of the major brands (I use Lyman) and a de-burring tool. Measure with a dial or digital caliper to keep the cases within plus or minus .002".

Mixed brand cases and un-uniformed case length will easily throw the accuracy off by several inches.

As far as primers are concerned, I use Win. Small Pistol primers (WSP). They are hotter than most standard primers, but not as hot as the mag. primers. Never had an issue with them even with the slowest powders.

Hope this helps,
Jeff

[Mavrick]

What is your alloy? You'll want a hard-cast boolit for this area. A commercial-cast boolit will quite often get the job done. If you cast your own, you might try Linotype or similar alloy. Even better, if you're casting(with hard boolits) you might try a larger lube die, probably a .358" or .359". For a small test, you might finger-lube(don't use KY) an unsized boolit.
I don't 'specially like magnum primers with 2400, as trying different primers from different makers will usually get the result I seek. 2400 is very easy to ignite.
Have fun,
Gene

[Bret4207]

With all due respect to Mavrick, you don't need a "hardcast" boolit, you need one that fits your gun. So lets start at the beginning- What mould design, PB or GC? You're sizing to in a .358 die, what are they coming out at, how long have the boolits been cast and what lube are you using? Is the gun clean of all fouling, what does it do with jacketed or factory loads and how many rounds does it have through it? Have you slugged or otherwise measured the cylinder or barrel.

Fit is king with cast. The hardest alloy you can get will not make up for poor fit.

[dromia]

Fit is king with cast. The hardest alloy you can get will not make up for poor fit.


Listen to Brett he has hit the nail on the head, once you've slugged your chambers, throat and bore you will then know if your boolit fits your gun.

That is the foundation of shooting cast that all the other variables are built upon.

[243winxb]

Your loading to hot. Alliant 2400 13.0gr Mag. primer with your 160gr bullet. If this load does not shoot well , change design of bullet.

[Mavrick]

Brett's right! My assumption was that you're using a plain-base boolit. If you have gc's, the boolit can be quite a bit softer. Fit is even MORE important.
My thoughts on the sizing I mentioned were based on the alloying harder so that the "as cast" would be larger, then you can size it down a little and still use a tighter fit.
If you use one of the other methods of hardening, the size won't change.
The velocity is WAY too high. Many times pressure will be way high, and not give extraordinary signs...Velocity ONLY comes with pressure....It's there whether or not there are other signs.
The lube you use will change things around, too. What are you using?
Have fun,
Gene

[fredj338]

Your loading to hot. Alliant 2400 13.0gr Mag. primer with your 160gr bullet. If this load does not shoot well , change design of bullet.

Yeah, I have to agree, your load is a wee bit hot. I pretty much max around 13.5gr of 2400 (no mag primer needed) w/ a 160grLSWC. Try some known ammo & see how it shoots. Could be you, could be the gun or load, but w/o a baseline, you are just chasing your tail.