Can a gas check change the POI?

[nueces5]

I put gas checks hornady and got good grouping.
One of my boolits had a check gas done with a check maker and the POI was markedly higher. The boolit is 314299 50% soww and 50% linotype, PC and lubricated with simple lube.
It was a single shot so I can not generalize. I use a load of 28 grains of Argentine powder that is similar to 3031. I do not measure it but it must be around 1900 FPS
I'm going to need more tests

[Conditor22]

In short - yes.
the squareness of the base affects the accuracy of a boolit.

One of the CB members is playing with long distance accuracy and ended up building a specialized GC seater that helped improve the accuracy.

[dimaprok]

I put gas checks hornady and got good grouping.
One of my boolits had a check gas done with a check maker and the POI was markedly higher. The boolit is 314299 50% soww and 50% linotype, PC and lubricated with simple lube.
It was a single shot so I can not generalize. I use a load of 28 grains of Argentine powder that is similar to 3031. I do not measure it but it must be around 1900 FPS
I'm going to need more tests

It's possible that one off had the gas check come off in flight. I've never seen one of my to come off bullets.

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[JonB_in_Glencoe]

I can't imagine POI changing markedly higher.
I concur with your opinion, more testing required.

[nueces5]

I can't imagine POI changing markedly higher.
I concur with your opinion, more testing required.

same boolit, same powder charge, same filler, only change the check
more test soon

[slim1836]

Those aluminum gas checks are lighter so they will fly further, that's why the POI is higher.

Slim

[stubshaft]

If they are lighter. then the velocity should be faster and they should strike lower.

[georgerkahn]

With no disrespect in any way intended or implied, I did not read, albeit I looked for, that ubiquitous "n" "n" stands for "number", and most all will agree that the greater the number is -- in this case, shots fired with Gas Check 'A', and then shots fired with Gas Check 'B' -- will produce the greatest probability of an accurate assumption if indeed the type of gas check makes a significant difference re point of impact... Of course, the firearm would need to be firmly secured -- or, a test barrel used -- to ensure it's in the same space for all shots. And, the temperature of barrel, as well as ambient air needs to be the same for all shots fired. And... and... and.
Note I'm being a tad jocund on what, to you, no doubt is a serious matter. However, I doubt if I'm alone in having similar, if not worse, targets using rounds from the same box of name-brand factory ammo. That you have a single shot is a "plus" as each shot will be the "first shot". However, the hold -- e.g., getting it EXACTLY as in prior shots -- will be the challenge!
YES -- you, indeed, are most correct in needing more testing/firing. Good luck. And "YES" -- I'd love to read the results you get.
Good luck!
geo