? about one shot in a 5 shot group opening up a group size.

[vermont2nd]

I have fired 10, five shot groups of this particular load, and there is always one shot that opens the group up (from what would be a .5" group) to an 1" to 2.33". I'm quite confident that the shot isn't pulled, as I'm shooting from a bench with a bi-pod in the front, and sand bags in the rear.

Is it reasonable to assume that this is attributed to seating depth? It's not always the same shot in the string that is off, nor is it always in the same orientation; meaning that the off shot isn't always at 1 o'clock, as an example.

All shots are fired slowly, and the rifle is cooled between strings. The bore is fairly clean, it had 30 rounds through it before the testing. It did this with the cold bore group, and with the subsequent groups. The barrel is fully floated, and the action is steel bedded.

Any ideas, or is there not enough info to go on? I intentionally left out bullet/powder/charge/case/etc, as to not muddle my inquiry.

 

[Guest]

you said you let the barrel cool between "strings" .... how bout between rounds.

My rifles begin to loose accuracy after 25- 30 rounds..... stainless barrels don't foul as far as I can see.

 

[vermont2nd]

you said you let the barrel cool between "strings" .... how bout between rounds.

My rifles begin to loose accuracy after 25- 30 rounds..... stainless barrels don't foul as far as I can see.

Sorry, I should have been more clear. By slowly, I meant about a minute between each round. With it being 40 F today, that was sufficient to keep the barrel cool.

 

[JD338]

vermont2nd

Three rounds test the load, 5 rounds test the shooter.

Try cleaning your barrel really well and make sure you have all the copper fouling out. Try shooting three shot groups and see where you are at.

JD338

 

[FOTIS]

Always 3 rounds for me . If that is not enough try 3 3 round groups for a better aggregate.

 

[vermont2nd]

vermont2nd

Three rounds test the load, 5 rounds test the shooter.

Try cleaning your barrel really well and make sure you have all the copper fouling out. Try shooting three shot groups and see where you are at.

JD338

The barrel was really clean, prior to the 30 that came before my tests.

So no one thinks that it could be a seating depth issue? The bullets, in the ones tested above, had quite a jump to the lands.

 

[Greg Nolan]

It could be a seating issue. Are all the brass the same OAL? If so then try varying the seating. It doesn't sound like stringing and it shouldn't be with the bedding system you have. If the loads are individually measured and the brass the same length it doesn't leave much else.
Greg

 

[DrMike]

Always 3 rounds for me . If that is not enough try 3 3 round groups for a better aggregate.

+1

Multiple groups when measured provide a realistic mean.

 

[R Flowers]

That seems like a pretty large spread on the flyer, but just on a lark, I would try switching primers.

A number of years back I had a custom 6mm Remington built primarily for long range prairie dog shooting. It has a heavy stalinless Shilen barrel, a McMillen stock, a Jewel triger, etc. It should shoot, right? Well, when doing load development I kept getting four shots in GREAT groups but ALWAYS a flyer.

I switched to Fed 210M primers and the flyers dissapeared. It is worth a try.

 

[jmad_81]

If you are getting four in a .5 MOA and a random shot out of the five opens it up I would be more suspecting of the brass. Do you weight sort your brass? flashole debur, uniform primer pockets? Check the concentricity of your loaded rounds, maybe you have some that are out of round. I have a good friend that had a custom 6-06 built and it would only group around 1 MOA. He weight sorted his brass and that cut it down to .25-.5 MOA.

 

[Antelope_Sniper]

Another possibility is the bi-pod. A bi-pod is not near as stable as sandbags.

 

[cloverleaf]

My rifle went the other way ...or seems to...Magnum primers opened up the group. But then that may be operator error.

 

[R Flowers]

The Fed 210M primers are not magnum primers they are "Match" primers.

 

[Richracer1]

The Fed 210M primers are not magnum primers they are "Match" primers.

Correct. Fed 215 primers are their "Magnum" rifle primers.

 

[nodak7mm]

I am with Speed Goat Sniper - Get rid of the bipod. Shooting them off hard surfaces can cause this kind of anguish.... Seen it several times....

Rod

 

[Ridge_Runner]

most of the time if a rifle is begging to tweak the COL it will shoot 2 separate groups within a 5 shot group.
RR