Load development process

Well, I’m wrapping up a frustrating weekend.  I recently bought a ruger gp100 for the purpose of shooting some distinguished revolver matches this summer.  I didn’t have much else to do, so I thought I’d spend some time trying to get a load that shoots.

I have a few hundred 158 grain Oregon Trail laser cast swc Bullets, so I’m starting there using 38 special mixed brass.  Yesterday I tried the loads that were suggested here as being ‘good’ loads.  No dice.  There wasn’t really groups.  Everything was scattered.

Today, I sorted the brass and chose to use 6 pieces of Remington brass for each trial.  I went from 2.5 to 3.6 grains with bullseye, shooting a full cylinder each time.  Some were better than others, the better ones would have 4 shots in a decent group, and then two that weren’t even on the target.

So then I decided to shoot 6 rounds individually through each hole in the cylinder and used some of the better loads from earlier in the day.  I thought maybe there were one or two holes that were really causing the group to open up.  After doing that exercise I saw no improvement and shots were everywhere.

I’m not quite sure what to do.  Full.disclosure, I was using a bag to rest my arms on, just below my wrist.  The gun is also open sights with the fluorescent green fiber optic sight.

So now 8m questioning whether I’m going about it right at all.  Maybe I should start at 25 yards and find something that shoots there first before going to 50.  Maybe I need to buy a rail for the gun and mount a scope for load development?  

I can’t believe the guns ‘bad’, so it must be me.  But if I can’t shoot any better than that off a bag I might as well give up the idea of shooting these matches.

I’m thinking the next thing to try will be using 357 mag brass and see if that produces some different results.  Any other recommendations?

Thanks, Neil

I had the same issues with revolver, went to factory ammo and it went away. Once that case is gone, I'll try again. One thing I. Looking at is going to be crimp. For some reason I have a taper crimp in my 357 die set... strainge...

Best to begin at 25 yds., at least 10 rounds per group.  IMHO.

Crimp the hell out of it, the factory does!

If you can find some, try it with factory 158 ammo; either Federal or Magtech.  If that shoots ok, proceed with load development.  When a reload shoots poorly in a gun known to shoot well, always suspect the bullet first.  It's the most critical component.

Bullet and crimp are important. It is possible for whatever reason your gun may shoot RN better than SWC. I have found crimp is a to taste of the gun thing, I would start in the medium range and tweak as needed. Some people like swaged more than hard cast as far a bullets go. I personally have had good luck with Zero 158 SWC and Brazos 158 RN. Revolver matches are fun glad to see someone new pursuing them.

A couple of points. 

The first is to manage your expectations and then also consider your abilities.  Most people without a ransom rest struggle getting any decent group at 50.  A lot of people with a ransom rest also struggle to get a group at 50.  Clamp the gun in a machinists vice  and it would shoot just fine.  That’s the ability limit which is mostly rooted in your vision.  

The second thing is to consider the DR match itself.  2/3 of the match is at the short line. While this is sustained fire and, whether shot double action or single action, groups are scattered, this is where top level accuracy is required.  

So my take is to load ammo that shoots at 25 yards.  30 shot group sizes.  I want the X ring obliterated and less than 10 Tens.  Check it at 50 and make sure that 15 of 20 shots are well inside the 9 ring.  With this approach you’ll get an 80 or better at 50 and 100s at the short line if you get 10 quality shots per target.  Then load 20 bazillion rounds of this ammo and go practice.

Revolvers are a different animal. If you test carefully you'll find that some chambers shoot better than others. As far as working loads that can be a long process. Start with light loads with a chosen crimp then work your powder up in say 2 grain increments until your satisfied. Then crimp heavier and use same loads you used before. Then do the same thing with different bullets since some barrels like certain bullets. Good luck!

Thanks for all the responses and suggestions.

I think I’ve got my expectations firmly set in reality, I just had no idea that just keeping them on the repair center paper at 50 yards would be a challenge.

For now, the Oregon trail 158 SWCs are the only bullet I have, so I have to stick with them.  I do have some round nose on order, but everything is back ordered.

I have Quite a few different powders I can play with though so I’ll start with those and vary the crimp.  I’ve got a roll crimp die, and it’s a pretty heavy crimp right now.  I’ll try a few different settings to see if I can come up with something better.

Thanks everyone, Neil

I have a GP 100, I used it as my centerfire pistol when I started shooting Bullseye matches.  It is very accurate, I was averaging about 89 from the long line with it in my first 6 matches.  

I found that it really likes the Remington target ammo, from the bulk pack.  130 grain fmj bullets at 800 fps.  I know that doesn't help for a DR load, but it does let me know that the gun will group when I find the right load.

I think it may like faster loads, maybe due to the barrel rifling twist.  It doesn't like the light HBWC loads I tried in it. 

If you want to mount a red dot sight, I recommend the Weigatinny rail, it is easy to mount.  You do need to remove the sights, but no drilling is required.

I used a GP100 to get me to DR - 50yd loads are a total pain in the you know what to make. I gave up and just bought factory rather than waste the time. I realise that may not be a good option right now :-)

I'd suggest getting the round crimp working at 25yds and practice the crap out of your timed/rapid handling - that's where most of the points are lost in DR. Once you can get some decent factory ammo then worry about the long line.

No luck finding factory loads to try. I checked gunbroker but the prices there are crazy.

I tried a few more powders and a wide range of crimps, including with 357 mag brass just to try something different.

I also shot a cylinder of some 125 grain xtp Bullets that I had loaded pretty hot. Those shot really well at 50, so now I’m just hoping the gun simply doesn’t like the swc style and it will like the zero round nose Bullets if they ever arrive.

Thanks again for the help and suggestions.

Neil

I will second the comment about round nose vs SWC. Word is SWC's are accurate to 49 yards. I personally have had good luck with round nose, both factory and reloads.

Received some round nose Bullets on Monday (thanks again chiz1180), and finally got to shoot some tonight.

What a huge difference!  I went from 6 shot groups that had shots 2 feet apart to almost consistently 4-5”.  2 weeks ago I was ready to chuck this GP100 in the dumpster, now there’s hope.

Thanks for the responses and suggestions above.  I would have never guessed the bullet type would make that big of a difference.

Sincerely, Neil

Just a thought you might try seating and crimping separately, sometimes if you crimp and seat at the same time you can distort the the bullet.

Glad the bullets are going to good use, 4-5" is not bad at all. Not sure if it was mentioned or not but some chambers can shoot more consistently than others.

Not 100% load related but revolver related, in slow fire I  load my "best" chamber for each shot. I found that single loading also helped keep me from rushing my shots and be more deliberate on my trigger squeeze.

troystaten wrote:Just a thought you might try seating and crimping separately, sometimes if you crimp and seat at the same time you can distort the the bullet.

That is something I started doing in the earlier round of development, but I didn’t see much improvement. Mi carried that process on into this round.

The first rounds I loaded were an improvement, and then I increased the crimp and the groups made another step improvement.

Thanks for the suggestion, Neil

chiz1180 wrote:Glad the bullets are going to good use, 4-5" is not bad at all. Not sure if it was mentioned or not but some chambers can shoot more consistently than others.

Not 100% load related but revolver related, in slow fire I  load my "best" chamber for each shot. I found that single loading also helped keep me from rushing my shots and be more deliberate on my trigger squeeze.

I don’t have a ransom rest and am shooting iron sights.  Do you think I’ll be able to discern differences in chamber accuracy with those ‘limitations’?

Depends on how well you can call the shot. I am able to do so and know a few others who can as well. It can be a time/ammo consuming process, but depending on how serious you are it could be worth it.