Groups opened up

[gau17]

It seems everyone assume it's the 'load'. IT AIN"T THE LOAD.
The only new differences are fire formed brass and maybe primer. Those 2 things do not increase group size by 100% assuming shooter and equipment didn't change.

If it's not you, the shooter... which is probable since you mentioned your groups had fliers the opened the groups up to 125%. And I'm assuming you're using a sturdy tightened down front rest and a firm rear bag. I'd suggest checking your equipment settings. Action screws (I've seen too many of these), scope mount screws, scope rings/screws.

I think this might be the case. You can also try loading again but use the chrono to see if the flyers are caused by you or the load. Maybe try using the round robin technique instead of shoot for groups.

[rstbkt69]

I have looked at the round robin ladder testing over and over. I cant get myself to try it. Its so outside of the way I have shot. Plus I don't have anything to hold the target paper i don't have either. The SD on my loads was all under 25. And the flyers weren't the ones that were out of range

[rstbkt69]

The thing that is bothering me and making me think that the load was off is that the two best performing bullets in a 4 shot group tightened up progressivly during development from .75 to .5 to .23. Didn't have anything that close in the last round. The first sets of 5 round groups had a flyer and then a small tight group. The first round with fire formed brass and flash hole work and my tighter pull into the shoulder was 5 random holes on all 5 bullets. I'm just go9ing to go with it being the nut thats behind the trigger and try adjusting that.

[huckberry668]

Load some dummies and mix with your ammo in the mag. Chamber and fire them as you normally would to see if you're pulling your shots or closing your eyes.

[gau17]

1. When you shoot do you lift your head up right away to look at the target? Try to keep you cheek weld the same throughout the 5 shots. DON'T MOVE YOUR HEAD.

2. try lowering the power on your scope. Have you heard of the saying "Aim small, miss small?

3. Trigger squeeze. focus on pulling the trigger to the rear. Don't anticipate the round going off. In a way let it scare you.

4. Use a rear bag.

[Whiterabbit]

Pretty sure it's neck tension here. Your brass was softer for the first firing. Now it's work hardened. OR, it's the fact that you didn't prep the new brass. In either case, there could be a big difference in case tension on that bullet.

[sonnyt650]

"no case prep at all" -- did you at least size the new brass, in other words did the neck tension get set at all for the new brass?

[rstbkt69]

Yes I sized the brass prior to loading. I didn't trim the neck, uniform the primer pocket, anneal or any of the other things we normally do. I'll try a rear bag. Wait i use a rear bag under the chassis. do you mean one up on my shoulder. I always keep my cheek weld till I see where the shot went. I do blink a little on the bang but I don't move around. trigger discipline is good. As I said during the initial development I would spot the shot and then make notes on speed for that specific round and where it landed, if I need to wait for the wind to calm down, What the measured airspeed was after the shot, etc. The last trip to the range I maintained cheek weld through all five shots.

[Whiterabbit]

i knew the fireformed cases would change the poi but didn't think it would change that much. Man that was over 200 rounds. And they were pretty sweet groups. Just wish the heat and humidity would go away. It would be easier to get out to the range. I have plenty of new cases left. i was saving them to add as the ones I'm shooting wear out.

Were the first groups shot in the winter? Are you using a temperature sensitive powder?

(I still think it is case neck tension. I've heard guys complain of the opposite, where new brass shoots bad and as soon as they fire it once or a couple times, the group sizes come back in.)

[rstbkt69]

All shot over the first 3 weekends of this July. H4350, I don't know if it is temp sensitive or not but each day of shooting was withing 10 degrees of each other when i started at 7:00am. Unfortunately I'm going to have to go with the big change and cause of this is how I braced the gun into my shoulder pocket. When i tried to keep the cheekweld I pulled tight and added more human factors into the shot. I'll be able to try it out with the same powder charge but unfortunately a shorter OAL this week. I can get out there any time the wind stops long enough after work. Looks like I may have to wait till Saturday though

[Whiterabbit]

It's good to change two variables at the same time, that ensures a scape goat is available when the results are not as expected.

I was thinking winter vs summer, and folks say H4350 is pretty temperature insensitive anyways. Compared to alternatives. I was just throwing it out there, but I'll still bet it is neck tension.

[rstbkt69]

I was going to anneal my once fired before I reloaded but I decided to wait till the second firing. Its too darn hot to be running a propane torch even if its automated anyway. Oh i could have blamed it all on the loads instead of figuring out its probably my shooting form, but then again if it is the loads it's still me. LOL. No chance for any scapegoats here. i am stuck with all fingers pointing to me no matter what i do. I could blame it on RCBS maybe. My bullet puller did break during this round of load development. Maybe it was the plastic boxes Sierra and Berger supply their bullets in. Is it working. Is someone else at fault now. i hope so.

I'll go back to the OAL I used before this one if/when the results throw bigger groups than before. if they are better Ill start from this point

[Whiterabbit]

you COULD confirm your old data as well by loading more 1x and new brass. That should confirm it's the brass or you.

[rstbkt69]

never thought of that actually. i get into a save the new brass for later mode and thats what happens. Thanks for the simple yet effective suggestion

[brl0301]

have you cleaned your rifle really well? I know my groups open up pretty dramatically when my barrel gets copper fouled. Doesn't take long to get fouled and doesn't clean up without some effort.