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Hot & Cold

 
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  #1  
Old 12-20-2010, 11:48 AM
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Hot & Cold

Howdy fellas,

My question is this. What are your feelings on hunting rifles that are the most resistant to heat/cold. I know anything with a heavy barrel would be ideal, but I hunt NW Montana (very steep terrain) so packing around a heavy rifle sucks (tried it with my 7wsm and don't want to do it again). My dilema is this, most of my rifles see use from 50 down to -15 degrees, and shoot well at those temps. What I'd like in my next rifle is something useful up here in these conditions, but will also keep it's zero (or at least closer to it) hog hunting in S Texas and Arizona at 100 or so degrees. I found out the hard way that my rem700 in 270win. doesn't like the heat difference at all (and it's not an option to hit the gun range down there). I hate using my Father-in-laws rifles when I'm down there because I'm a southpaw. I should probebly just put a synthetic stock on the 270 and chalk it up to humidity warping the stock a bit or something, but this seems like a good excuse for a new rifle. Also do you think stainless vs blued makes a huge difference. Any in put would be great. Thanx.
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Old 12-20-2010, 02:13 PM
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Re: Hot & Cold

Quote:
Originally Posted by threejones View Post
Howdy fellas,

My question is this. What are your feelings on hunting rifles that are the most resistant to heat/cold. I know anything with a heavy barrel would be ideal, but I hunt NW Montana (very steep terrain) so packing around a heavy rifle sucks (tried it with my 7wsm and don't want to do it again). My dilema is this, most of my rifles see use from 50 down to -15 degrees, and shoot well at those temps. What I'd like in my next rifle is something useful up here in these conditions, but will also keep it's zero (or at least closer to it) hog hunting in S Texas and Arizona at 100 or so degrees. I found out the hard way that my rem700 in 270win. doesn't like the heat difference at all (and it's not an option to hit the gun range down there). I hate using my Father-in-laws rifles when I'm down there because I'm a southpaw. I should probebly just put a synthetic stock on the 270 and chalk it up to humidity warping the stock a bit or something, but this seems like a good excuse for a new rifle. Also do you think stainless vs blued makes a huge difference. Any in put would be great. Thanx.
Most POI changes due to extreme temp changes are either bedding problems or just as likely, pressure problems due to both the air, and powder temps. i.e. colder=less pressure and lower POI and hotter=more pressure and higher POI. Some powders are considerably worse for this than others. The answer is to make sure your rifle is well bedded (synthetics are USUALLY better than wood) for holding zero, mostly because of moisture content. Make sure you use a powder that is not as sensitive to temp changes and try to zero in conditions as close to hunting conditions as possible. Hope this helps......Rich
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Old 12-20-2010, 05:22 PM
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Location: NW Montana
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Re: Hot & Cold

Thanx Rich, I'll check on the powder. It's at least a step in the right direction. Unfortunately, zeroing in similiar conditions isn't a possibility on this one. It's 12 degrees here and in the 80s in TX. I'd love a chance to get zeroed there, but the nearest range or good place to sight-in (in TX)is way too far away to hit before hunting. For now I'll swap stocks (wanted to anyway, just didn't have a good enough reason) and check on different powders. I guess what I was wondering is- since I've been looking to pickup a new rifle anyway, if there was a specific brand of rifle, or barrel material, etc that would be less prone to shifting zero with the heat changes than another.
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Old 12-20-2010, 05:53 PM
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Re: Hot & Cold

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Originally Posted by threejones View Post
Thanx Rich, I'll check on the powder. It's at least a step in the right direction. Unfortunately, zeroing in similiar conditions isn't a possibility on this one. It's 12 degrees here and in the 80s in TX. I'd love a chance to get zeroed there, but the nearest range or good place to sight-in (in TX)is way too far away to hit before hunting. For now I'll swap stocks (wanted to anyway, just didn't have a good enough reason) and check on different powders. I guess what I was wondering is- since I've been looking to pickup a new rifle anyway, if there was a specific brand of rifle, or barrel material, etc that would be less prone to shifting zero with the heat changes than another.
No difference that I am aware of. Someone else may have some knowledge that I don't have? I can tell you for sure that the 68 degree difference in temp that you refer to can make a big difference with some powders and could definitely affect POI. What are you loading for and what is your powder? The affect of degrees of air temp alone will cause considerable difference in POI at long range since cold air is more dense. Add to that the powder temp, and you can REALLY have issues. I would suggest that you go on line to JBM ballistics under trajectory and plug in the variables. You will soon see how much affect you have. Some powders are known to vary as much as 150'/second with extreme temp changes.......Rich
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Old 12-20-2010, 07:35 PM
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Join Date: Sep 2010
Location: So. California
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Re: Hot & Cold

Hi TJ,

I did not see you mention what Type of POI change you had. Was it vert, horizontal, or a bit of both?

I have a friend who is an avid hunter and shoots a 270 win. He used to use Varget, but this year decided to test out IMR8208xbr. He is the type that wants accuracy, relatively low recoil, and temp stability. So he was willing to give up about 75fps or so on the powder change (he does not run hot loads, hence only 75fps change). He says that his POI was pretty minimal this year.

I used to have a 270 a couple years ago myself. A good friend from out of state talked me out of it when his rifle took a bad fall on a hunt.

Anyhow, I used to use a couple of loads for different purposes:
-- 130gr Nosler Ballistic tip hunting - H4350 - Win brass - Fed 210m primer. This was a real good load. As far as I know he uses it in most of his shooting to this day. I wont list the powder charge, it was warmish, but not overly hot.
-- 150gr Berger Hunting VLD - H4831 - Win brass - Win LR primer. This was another nice load.

Both of these loads are pretty temp stable. I had an RL22 load, but the H4831 replaced it, as it was definitely less temp sensitive. I use both actual field testing, and chrono data, in summer at above 100 deg. F. and in the winter usually around 30-40 deg. F. I was "Lucky" with the H4831 and was able to test it at about 15 deg at about 6500 feet one year. The load did real well. I don't have the numbers right at the moment, those went with the stick when I sold it. The guy is an avid reloader. I never replaced my 270 as I used my 6.5 swede most of the time.

Anyhow, a wood stock can of course warp and cause problems too.

Good shooting,
Gary

Last edited by diriel; 12-20-2010 at 07:40 PM. Reason: Clarity
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  #6  
Old 12-20-2010, 08:28 PM
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Re: Hot & Cold

Rich- Thanks for the tip on JBL. I'm pretty sure the powder was the main problem. I'd been using RL22 w/130g nosler bt. They've been very consistant around here, but the temp difference between sight-in and hunting is usually only a few degrees. I'll load up some rounds with H4831 and see what happens. I'll be in TX for xmas and will hopefully have some time to hit the range to test em.

Gary- Those look like pretty good rounds. I'll give em a try next time I load. The three shots I got off were all over. 1ft left at +-125yrds. 6in low but dead on at +-75yrds, and one that was pretty high (who knows just how high)and a bit left at 175 (I think I over compensated for the low shot). I had a good rest on all three shots. I went to the range when I got home and put five shots inside 1.5 @100yrds from the same rest (my pack) with the same batch of rounds.

Reguardless of loads, I'm headed to Columbia Falls tomorrow to pick up a Lone Wolf composite/glass stock. Manners or HS would be nice, but I thought I'd try the local guys out. Anyone have any feedback on Lone Wolf?

Thanx for the help
Cody
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  #7  
Old 12-20-2010, 08:42 PM
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Location: Grantsville Utah
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Re: Hot & Cold

The reloader powders give great velocity and good accuracy but are some of the worst I've seen for temp sensitivity......Rich
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