Bench Mark for Load Testing

[gunnermhr]

What do you use as a bench mark when developing new loads? Distance, Number of Shots and Group size and theory's behind it.

Typically I like a good solid 5 shop group at 200 yards at no more than 1/2" This weekend I printed 2 groups. Dasher shooting 105 Hybrids, one with CCI Primers shot .375" one with GM205M Primers was .325" Obviously I need to check constancy with both loads to determine which is the keeper, but I think .050" is a hard number to make that determination with one side by side group comparison.

My thought is any further and the elements play into the group size too much, Any closer and I have a hard time determining what is best. 3 shots seems like not enough and 5 shots sometimes seems like too much. If I print 3, 5 shot groups and have one flyer I don't get too excited.

 

[Fotheringill]

Shots in a group are like prunes. Are three enough? Are five too many?

Just pick one and stick with it.

 

[savagedasher]

What do you use as a bench mark when developing new loads? Distance, Number of Shots and Group size and theory's behind it.

Typically I like a good solid 5 shop group at 200 yards at no more than 1/2" This weekend I printed 2 groups. Dasher shooting 105 Hybrids, one with CCI Primers shot .375" one with GM205M Primers was .325" Obviously I need to check constancy with both loads to determine which is the keeper, but I think .050" is a hard number to make that determination with one side by side group comparison.

My thought is any further and the elements play into the group size too much, Any closer and I have a hard time determining what is best. 3 shots seems like not enough and 5 shots sometimes seems like too much. If I print 3, 5 shot groups and have one flyer I don't get too excited.

Why shoot more then two shots ?
Your group will never get better then the second shot . Just change to another target and shoot 2 more Then another target 2 more . If meisure the 3 two shot targets and add them together then divide by three
You have the same results. Larry

 

[dmoran]

Vertical dispersion at the intended distance, is my benchmark.
Where to say the vertical dispersion a load has built into it, is all the better it will ever do.
To have a chance at better, have to tune the load (or setup) to produce less vertical.
ES data is a handy reference, but the actual target at the intended distance tell the true tales - IME
Vertical is the key... or so is my 2-cents
Donovan

 

[BoydAllen]

The farther the target, the greater the influence that conditions will have. For me, testing is all about controlling variables to the greatest extent possible. IMO you would have very likely seen the same or more difference between the size of the groups if they had been shot with identical loads.

A group of my friends shoot informally at plates at distances between 700 and over 1,100 yards. One of them, who builds his own rifles just for those "events", does all of his testing at 100 yards (with a couple of wind flags between him and the target) with bullets of the highest available BCs for their calibers, shooting beside a LabRadar chronograph. Between the test targets and the chronograph readings he is able to come up with loads that seem to do pretty well at the distances that he shoots. Certainly the kind of shooting that they are doing does not allow measurement of results that is as precise as would be the case with paper targets, but even so, he has learned quite a lot, and the all seem to have a lot of fun.

 

[kyreloader]

My benchmark for loads for Fopen shooting is 1" five shot groups at 300 yards. If I can get that, I test at further distance as the drive to 600 yard range is twice my drive to a 300 yard range. If I had a close 600 yard range, my benchmark would be 2" of vertical dispersion at 600 yards for a 5 shot group. This is for LR Fclass shooting.

 

[dmoran]

@BoydAllen -
Myself I have and can produce great accuracy loads at 100yds that would be more then capable to a number of disciplines and usages. But for 1000-BR, they were about a 60/40 chance with some major flops occurring in the 40%. Unlike since and going at it right at 1000, I know what there capable of, both good & bad, at all times, with out the teasers or liars sort to speak !.!.!

For instance, currently have a LT-Gun load that is capable of mid 2" groups from 5 shots, and a HV-Gun capable of mid 4" groups from 10-shots. To get them better, I do not believe I could ever find it at 100yds with out high risks of flops. The vertical dispersion at 1000yd of every aspect I may try/change is instant and factual feedback.

I sacrificed a lot to have my own 0 to 1000yd private range. A lot of work, expense, and up keep goes with, so that I don't have to travel to find the distance anymore. But did and would travel again if I didn't have it.
Donovan

 

[Northridge]

Why shoot more then two shots ?
Your group will never get better then the second shot . Just change to another target and shoot 2 more Then another target 2 more . If meisure the 3 two shot targets and add them together then divide by three
You have the same results. Larry

But it can get a lot worse than the 2nd shot.... I would recommend no less than three shots but five tells more.....

 

[dmoran]

But it can get a lot worse than the 2nd shot.... I would recommend no less than three shots but five tells more.....

Shawn -
There's a 24% probability your input will be right from a 3rd shot. 37% by a 5th shot, and 67% probability by a 10th shot. But for the holy grail Mantanee gong matches, those retaliative percentages must not mean much. Speaks probable to what level they demand doesn't it... lol
Donovan

 

[Down South]

My benchmark for loads for Fopen shooting is 1" five shot groups at 300 yards. If I can get that, I test at further distance as the drive to 600 yard range is twice my drive to a 300 yard range. If I had a close 600 yard range, my benchmark would be 2" of vertical dispersion at 600 yards for a 5 shot group. This is for LR Fclass shooting.

Same here, my local range only goes out to 300 yards. I'll node test at 100 or 200 then fine tune at 300. I test just after daylight when the winds are down using a front rest on a concrete bench. My match loads usually shoot 5-10 shot groups right at 1 inch consistently at 300. Every load i've worked up that consistently shot tight at 300 has shot well at distance (600-1000). This is my FTR rig (.308).

 

[CharlieNC]

Depends on your shooting application. If you are primarily interested in accuracy, such as a PRS shooter wanting to hit a steel plate anywhere, then the focus is on achieving a stable poi. In that case an ocw/ladder type of load development only requires 2-3 shots per item to map the area of minimal poi sensitivity. To understand achieving small group size only, I can only say measuring ES (whether group size or chrono) is far inferior than measuring SD as the response from strictly a statistical perspective. Using SD to develop loads to achieve small groups is a more robust approach.

 

[KWeigel]

Same here, my local range only goes out to 300 yards. I'll node test at 100 or 200 then fine tune at 300. I test just after daylight when the winds are down using a front rest on a concrete bench. My match loads usually shoot 5-10 shot groups right at 1 inch consistently at 300. Every load i've worked up that consistently shot tight at 300 has shot well at distance (600-1000). This is my FTR rig (.308).

Agree. I can shoot 300 out of my back door. I however start right at 300. Fine tune then verify at my 600 at my buddies down the road. I have started right at 600 but can't load in the hay field the best. So I do it at home, stepping in and out till it shoots. Once satisfied lug it 2 miles to my buddies and verify. So far has worked out pretty well for me.

 

[Down South]

Agree. I can shoot 300 out of my back door. I however start right at 300. Fine tune then verify at my 600 at my buddies down the road. I have started right at 600 but can't load in the hay field the best. So I do it at home, stepping in and out till it shoots. Once satisfied lug it 2 miles to my buddies and verify. So far has worked out pretty well for me.

You are a lucky man to be able to shoot out your back door!.......