We all know that barrel temperature can cause a big shift in POI in a rifle. What about a pistol? What about a long barrelled pistol (7.5", 9.5")? When does it become significant? What have those of you with lots of experience seen in this regard?

Sig
<br>I dont have an answer for you . I wish I did. I am working with an engineer freind of mine and he is doing some testing on the effects of temperature. Something I have always wondered about is with a scope mounted on the reciever in say 70 degree weather both would be a certain length. Drop 50 degrees from that and will the aluminum contract at exactly the same rate as steel ? Is there enough difference to matter ? What effect does it have on the scope ? Point of impact ? If the scope contracts more than the reciever does the scope bend or slide inside the rings ? Hopefully pretty soon I will have some good solid data to support whatever we find. I do know that you can take a Remington factory gun and torque the barrel to say 100 foot pounds at 80 degrees then heat the barreled action to about 300 degrees and get an average of about an eighth of a turn ! Enough to get the headspace way out. Why would I try this ? To find out if the threaded joint is stable at that temperature. If its not then the barrel can move around slightly inside the reciever ring. Not good for accuracy. I will post the results when I get them.
<br>Charlie Sisk

Charlie,
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<br>What about Harold Vaughn's idea to use ramp threads? Would this be a more stable joint?
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<br>Blaine

Dang Charlie, now you done went and gave me ideas that are going to keep me awake at night. After lapping in my rings and shimming the mounts I have to worry if the things are expanding at the same rate when they get hot or cold. What's that going to do to my accuracy? How long before it just pulls my scope in two? What am I going to do now?

The handguns that I think of as handguns -- omitting, that is, the XP-100s, Contenders, and Encores with long RIFLE barrels and cartridges -- all have short barrels and fire moderate-pressure cartridges. Therefore, I'd expect their drastically reduced barrel time and barrel droop, as well as their significantly lower maximum peak pressures, to have negligible effects in comparison with those typical with rifle barrels and cartridges.
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<br>But this is just my conjecture. I don't know and have no way to tell how accurate it may be.

My original post was prompted from what could be direct observation of POI shift with tempertature. Certainly the POI was shifted but was it temperature or perhaps my hand was getting tired and my aim was getting sloppy. I was shooting a SRH in 454 Casull with a 7.5" barrel. If I had a vise I could lock it up in and try it that way, I would know - maybe someone else has done this?

Sig
<br>Sorry for making a response that had little to do with your post. Part of my brain and hands were thinking one thing and the majority of my brain was asleep. I will try to do better.
<br>Charlie Sisk

Charlie,
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<br>No need to apologize for an interesting post. Please let us know what you learn about the temperature effects on the scope.