testing reloads

[rclouse79]

I loaded 6 groups of rounds with different seating depths. There are four bullets in each group. I am going to the range to test them this weekend and want to limit other factors that effect the accuracy besides the seating depth.

A). How long do you wait between shots or groups to reduce the effect of barrel heating on accuracy? I was thinking about a minute between shots and 10 minutes between groups, but that is not based on anything.

B). How often would you clean your barrel if you were going to take 24 shots at the range? I have been cleaning my barrel around every 15 shots, as advised in the cleaning section of Lyman's reloading manual. If I clean half way through should I shoot some fowling shots before resuming the test?

C). Anything besides heating and cleaning that will effect the test?

 

[Mikecr]

How long do you wait between shots or groups to reduce the effect of barrel heating on accuracy? I was thinking about a minute between shots and 10 minutes between groups,

Without knowing the cartridge, it's hard to guess at barrel cooling betwen shots. For 'fast grouping' I prefer a barrel heat up no more than allowing me to wipe the barrel with the back of my hand, without screaming like a little girl in front of other shooters..
But your ten minute rule will produce the very worst in performance. With cold bore testing, which I do mostly, a 10min shot interval is as ugly as it gets. It's worse than 5min, 30min, 1hr, 2hr, , etc.
And that's fine down the road. Eventually I wanna see the worst.
But early in load development(with 26wssm & smaller), it's 1min/sht, every 30mins, and the first group don't count(fouler, adjuster).

How often would you clean your barrel if you were going to take 24 shots at the range? I have been cleaning my barrel around every 15 shots, as advised in the cleaning section of Lyman's reloading manual. If I clean half way through should I shoot some fowling shots before resuming the test?

Absolutely horrible idea.
You should not throw barrel cleaning into initial load development if it changes everything. I say 'if', but it typically does. Hopefully your barrel does not copper foul so bad that this becomes a necessity. If it does, shoot a round of Tubbs FinalFinish bullets through it, and consider coating bullets, and same pre-fouling for the barrel. You need to get through your testing with as few factors as possible.

Anything besides heating and cleaning that will effect the test?

Tons of things... Your rest, the sun, the wind, the temps, bugs, goat chewing on your guncase, farmer's daughter picking up brass in daisey dukes.. Rednecks asking stupid questions while cousin Bo carries more painted cinder blocks downrange to shoot at(they haven't discovered paper yet)..

 

[rclouse79]

Thanks for the reply Mike. I was shooting a round every minute or two the last time I went out. I noticed that one of my groups formed a perfect 45 degree line with the first shot at the lower left and later shots moving up and to the right by nearly the same distance each time. I was reading another post on here and someone attributed that to barrel heating. I am shooting a tikka .270 with 130 grain barnes ttsx.
I was wondering if the ten minute rule was something you found with a particular gun, or if that would apply to all guns?

 

[Derek M.]

If you really want to be fair to your load testing then each group will travel down the same path. So, to that, you can take your cleaning equipment and clean between every group, take some extra factory ammo or other non testing loads and use them as foulers. This also allows for barrel cooling. I use to do this and found it to work very well but was time consuming.

So, you'd start with a clean, dry bore, fire a fouler, then a 4 shot group, then clean, let bbl cool down completely, and start over.

I always prop my rifle upright between groups as this seems to assist cooling, letting bore heat dissipate more quickly.

Most of the time I don't do the method above anymore simply because I'm lazy, and don't have the time, plus I'm at the mercy of cease fire at the range. I usually load the number of rounds for testing which would include a regular cleaning anyway, which is about 21 to 24 total rounds while doing load development and this system has served me well also.

I think the real key is starting with a barrel that has a few rounds through it and is "broken-in" to begin with. Start with a clean bore and shoot 20 or so rounds, even up to 30 before a thorough cleaning again. The key in my opinion is barrel cooling.

 

[Mikecr]

I was wondering if the ten minute rule was something you found with a particular gun, or if that would apply to all guns?

This has applied to my guns which are under 50gr of powder(223,6br,6xc,6.5wssm). It seems a transient where the barrels are cooling, but not enough to be stable in POI.
Your barel will get hotter. So the ugliest barrel temp interval would likely be 20-30mins.

Derek, you do realize your advise was completely self contradicting right?
You tell the man to clean after every group(which is insane).
Then you tell him just what I told him to do(complete testing before cleaning)..

It takes special efforts to get everything stable with a single fouler. It just doesn't happen by chance.

 

[Derek M.]

Derek, you do realize your advise was completely self contradicting right? You tell the man to clean after every group(which is insane).
Then you tell him just what I told him to do(complete testing before cleaning)..

re-read my first paragraph cautiously.

 

[rclouse79]

I finally found a combination that gave me a sub minute of angle group. I shot a 0.610 4 shot group from 100 yards with 54.5 grains of H4350 and a 130 grain barnes ttsx seated 0.060 off the lands. I am pleased I got a decent group because that is the bullet I was hoping to shoot for my mule deer and elk hunt this year. Thanks again for the advice.