change of poi as gun warms up?

[svandamme]

I'm relatively new at this, have about 350 rounds down with my PM7.
It shoots low, have adjusted the sights up.. But i get the idea that the point of impact changes as the gun warms up?
At 10 meters, If i aim for dead center when cold , i'm below the black.
But after 30-35 rounds, i'm right on the money where i aim.

Had this several times now.. but not sure if i am doing this myself, or does the POI considerably change as the gun warms up? :confused:

[zenfly]

If you're new it may be a good idea to have someone else who you know in a good shooter run it for you off a bench and bags.. Also I have a diopter that goes on my glasses that help you get the target and the sights more in focus at the same time.. I bought it back when i used to shoot a 85lb steel rams at 200yds. in IHMSA.. A very handy item..

Edit: I just searched for a clip on diopter and can't find one... Get a pair of old glasses and use a piece of tape with a 1/16" hole punched in it and tape on the lens over your dominant eye and peek through the hole.. you'll see real cheep how it works with the pistol sights..

[svandamme]

I know i'm crap with the 45 offhanded, but 2 handed i've managed some reasonable groups. And it's all in the center, it's just that If i point center when it's cold, i get a low group, reasonable group, but low and it seems to creep up when it warms up.

Guess it's just me then?

[douglas_knott]

i personally haven't heard of a gun doing what your explaining. are you free handing the shots or using a bag? try using a bag starting out and see how it shoots.

[Dave Waits]

Sounds like you're pulling down on the trigger. Try shooting from a rest cold.

[Riverpigusmc]

I agree with Doug and Dave..shoot from a rest and then you can determine if it's you or the gun..only time I've heard of that is from a full auto weapon when the barrel was HOT..doubt thats your trouble

[svandamme]

wildo, thanks for the feedback

[douglas_knott]

wildo, thanks for the feedback

let us know the outcome please

[svandamme]

never mind the .22 holes, i just re-used somebody's card


first set of 10 rounds right handed @ 10 meters

http://forums.pelicanparts.com/uploads19/right+handed1319975866.jpg

second set of 10 rounds right handed @ 10 meters

http://forums.pelicanparts.com/uploads19/right+handed+21319975910.jpg

10 rounds, 2 handed @ 25 meters (bad pic but you get the idea)

http://forums.pelicanparts.com/uploads19/25+meter+right+handed1319975937.jpg


2 x 10 rounds @ 10 meters green is right handed, purple is lefthanded

http://forums.pelicanparts.com/uploads19/left+and+right+handed1319975992.jpg


I first ran 50 rounds with a Ruger .22 as warm up...Which improved my .45 results considerably, all in all, i guess this answers my question : It was me, not the gun.
Quite happy with this result, especially since i'm a bit hungover this morning :D

[jcc7x7]

You might try a different lube on your pistol that may be more heat resistant and not cause binding. If the pistol is changing POI when hot something is binding. Hope this helps

[Pappy]

This is not good news if the barrel has not been stress relieved. You may have a warped barrel which changes POI when warmed up. Sorry to say this...

[svandamme]

snip
2 x 10 rounds @ 10 meters green is right handed, purple is lefthanded

http://forums.pelicanparts.com/uploads19/left+and+right+handed1319975992.jpg


I first ran 50 rounds with a Ruger .22 as warm up...Which improved my .45 results considerably, all in all, i guess this answers my question : It was me, not the gun.
Quite happy with this result, especially since i'm a bit hungover this morning :D



This is not good news if the barrel has not been stress relieved. You may have a warped barrel which changes POI when warmed up. Sorry to say this...




I already indicated that the issue was fixed by training the operator.

[Pappy]

I already indicated that the issue was fixed by training the operator.

Did not notice this...but will wait till the hangover is gone....

[Hodawg]

Glad to hear you figured out the problem, svandamme.

Just for shirts and gurgles, in case this problem ever comes up again with another shooter, svandamme's situation sounds like a classic case of anticipating recoil. That causes most shooters to dive forward, hence a low shot. After a few magazines full, the shooter gets more relaxed and no longer anticipates recoil, then the shots come up to the POA.

Just a thought based on his description of events.

Ken

[DaFadda]

My take is that when the gun.......and you......are cold.....poi will be diferent. Once you warm up.....not the gun....that is the diff in poi. Try having a friend warm up the gun for u....then shoot it urself..... Post the results for us?

[Hodawg]

My take is that when the gun.......and you......are cold.....poi will be diferent. Once you warm up.....not the gun....that is the diff in poi. Try having a friend warm up the gun for u....then shoot it urself..... Post the results for us?
A good suggestion for ruling out metallurgical factors.

[Dave Waits]

The only time you'll see a cold-bore change of impact is in a long-barreled gun like a rifle and normally, it's usually the first round out of the tube.

[DrHenley]

I first ran 50 rounds with a Ruger .22 as warm up...Which improved my .45 results considerably, all in all, i guess this answers my question : It was me, not the gun.


I think your grip loosens a bit when you get a little tired from gripping too tight and anticipting the recoil, allowing the muzzle to flip more. Warming up with another gun gets you past the too-tight grip phase.

I've noticed the same phenomenon, using a 22 first improves my groups considerably.