Temperature effect on pistol loads
- Thread starter kwak
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Re: Temperature effect on pistol loads
If you are shooting across a chronograph, like trying to make major power factor for an IPSC match, you need to be aware that ALMOST all powders will drop off in velocity as the temps get colder.
SOMETIMES... keeping your magazine in your shirt pocket inside your jacket / coat will help some. But don't count on that.
The only way to make sure how your loads will react to cold or extreme cold is to shoot them across a chronograph with your pistol.
Keep accurate records.
I hope this helps.
Good luck.
If you are shooting across a chronograph, like trying to make major power factor for an IPSC match, you need to be aware that ALMOST all powders will drop off in velocity as the temps get colder.
SOMETIMES... keeping your magazine in your shirt pocket inside your jacket / coat will help some. But don't count on that.
The only way to make sure how your loads will react to cold or extreme cold is to shoot them across a chronograph with your pistol.
Keep accurate records.
I hope this helps.
Good luck.
Re: Temperature effect on pistol loads
I agree with everything that Victor has said -- chrono and keep records.
But, I'm very surprised that you're seeing the issue. What that says to me is that your standard .40 S&W load is way too soft.
As an IPSC shooter, we sometimes worry about cold days where we might not make major power factor if pushing the edge. For example, if my standard match load is at 167 PF (velocity x bullet weight/100000) for a nominal summer day of 70 degrees, then I may be concerned shooting a match at 45 degrees (if they're going to chrono me -- typically only major matches). I might lose enough velocity to go below 165 PF, thereby minor.
But, the gun will still function, I'll just have to shoot more As. With pistol loads you should have no problem with gun function regardless of temp but that's assuming you're within the 'window of operation'. It doesn't sound as though you're there. I know plenty of folks that shoot minor PF loads all the time for different reasons -- their guns still function though.
What velocity and bullet weight is your load?
I agree with everything that Victor has said -- chrono and keep records.
But, I'm very surprised that you're seeing the issue. What that says to me is that your standard .40 S&W load is way too soft.
As an IPSC shooter, we sometimes worry about cold days where we might not make major power factor if pushing the edge. For example, if my standard match load is at 167 PF (velocity x bullet weight/100000) for a nominal summer day of 70 degrees, then I may be concerned shooting a match at 45 degrees (if they're going to chrono me -- typically only major matches). I might lose enough velocity to go below 165 PF, thereby minor.
But, the gun will still function, I'll just have to shoot more As. With pistol loads you should have no problem with gun function regardless of temp but that's assuming you're within the 'window of operation'. It doesn't sound as though you're there. I know plenty of folks that shoot minor PF loads all the time for different reasons -- their guns still function though.
What velocity and bullet weight is your load?
Re: Temperature effect on pistol loads
I have to admit that my loads have never be chronographed. I was using about 4.0 grains of clays with a 165 grain berrys flatpoint. They were fine until the temp in the garage dropped to 48. I switched to clays because it burns very clean in the 45 and 38 loads. I was using Unique and IMR 7625 in the 40 and noticed that the 40 gun was 3-4 times as dirty than the 45 for the same amount of shooting. Thanks
I have to admit that my loads have never be chronographed. I was using about 4.0 grains of clays with a 165 grain berrys flatpoint. They were fine until the temp in the garage dropped to 48. I switched to clays because it burns very clean in the 45 and 38 loads. I was using Unique and IMR 7625 in the 40 and noticed that the 40 gun was 3-4 times as dirty than the 45 for the same amount of shooting. Thanks
Re: Temperature effect on pistol loads
OK, that additional data is helpful although not what I would have expected given your initial question.
Clays:
What's your OAL and what gun are you shooting those loads through?
Reason why I'm asking is that Clays is a pretty fast powder for .40 loads. Plenty o' folks use it but you have to tread carefully. It looks like you're just above max charge that Hodgdon lists:
165 GR. SIE JHP Hodgdon Clays .400" 1.125" 3.5 851 29,900 PSI 3.9 897 33,300 PSI
(This is for Sierra's full jacketed JHP which may react differently than Berry's plated bullets)
Any pressure signs? Was the gun short cycling or failing to extract?
IMO: reloading without a chrono is a crap shoot. Get a $100 Chrony at least.
Also, there's some info in the Enos site links below that may help:
http://www.brianenos.com/forums/index.php?showtopic=112240&st=75 and
http://www.brianenos.com/forums/index.php?showtopic=105461&st=0
Note: While I'm sounding the "watch" alarm, I'm a fan of fast powders and heavier hardcast bullets for .40. I use an even faster powder (N310) but I worked up very cautiously, got a full brief from an experienced pro that turned me onto it, chrono'd along the way, loading long, through a supported barrel STI, etc. But, it's not without risk -- a double charge would be catastrophic.
OK, that additional data is helpful although not what I would have expected given your initial question.
Clays:
What's your OAL and what gun are you shooting those loads through?
Reason why I'm asking is that Clays is a pretty fast powder for .40 loads. Plenty o' folks use it but you have to tread carefully. It looks like you're just above max charge that Hodgdon lists:
165 GR. SIE JHP Hodgdon Clays .400" 1.125" 3.5 851 29,900 PSI 3.9 897 33,300 PSI
(This is for Sierra's full jacketed JHP which may react differently than Berry's plated bullets)
Any pressure signs? Was the gun short cycling or failing to extract?
IMO: reloading without a chrono is a crap shoot. Get a $100 Chrony at least.
Also, there's some info in the Enos site links below that may help:
http://www.brianenos.com/forums/index.php?showtopic=112240&st=75 and
http://www.brianenos.com/forums/index.php?showtopic=105461&st=0
Note: While I'm sounding the "watch" alarm, I'm a fan of fast powders and heavier hardcast bullets for .40. I use an even faster powder (N310) but I worked up very cautiously, got a full brief from an experienced pro that turned me onto it, chrono'd along the way, loading long, through a supported barrel STI, etc. But, it's not without risk -- a double charge would be catastrophic.
Re: Temperature effect on pistol loads
OAL is 1.1305 Sig Sauer X5 The gun ejects the case but fails to load the next round into the chamber. No over pressure signs what so ever. Thses worked fine until they got cold. Everything is fine with both my 38 and 45 clays loads same temp. I would like to assume that they are very light but you thought they were max. Thanks again I read the additional info but most of that was with 180 grain. I have some 180 maybe I will give them a try.
OAL is 1.1305 Sig Sauer X5 The gun ejects the case but fails to load the next round into the chamber. No over pressure signs what so ever. Thses worked fine until they got cold. Everything is fine with both my 38 and 45 clays loads same temp. I would like to assume that they are very light but you thought they were max. Thanks again I read the additional info but most of that was with 180 grain. I have some 180 maybe I will give them a try.
Re: Temperature effect on pistol loads
Good data. With your OAL and the X5, that does alay any fears. That data I displayed was directly from Hodg's loading manual.
I've played with many different .40 loads and I tend to prefer heavier bullets with faster powders for a softer recoil impulse. That's why I'm basically shooting a .45 load currently through my .40 (STI) -- very soft round (and accurate). Admittedly, it's an atypical load.
But, going with a 180gr'r with Vit N320 would be one to check out. Vit really does make some great pistol powders that aren't terribly temp sensitive (and very clean burning). I don't remember the exact stats from the past few USPSA Nationals but there's a reason why Vit is so popular with folks that shoot xx,000+ pistol rounds per year. Best wishes.
Good data. With your OAL and the X5, that does alay any fears. That data I displayed was directly from Hodg's loading manual.
I've played with many different .40 loads and I tend to prefer heavier bullets with faster powders for a softer recoil impulse. That's why I'm basically shooting a .45 load currently through my .40 (STI) -- very soft round (and accurate). Admittedly, it's an atypical load.
But, going with a 180gr'r with Vit N320 would be one to check out. Vit really does make some great pistol powders that aren't terribly temp sensitive (and very clean burning). I don't remember the exact stats from the past few USPSA Nationals but there's a reason why Vit is so popular with folks that shoot xx,000+ pistol rounds per year. Best wishes.
Re: Temperature effect on pistol loads
Thanks again , I will give the Vit a try. Because I am frugal I used the Clays. It works very good in my other loads, it is very clean, it is cheap, and it requires 5o percent less powder and the paper I shoot at can't tell the difference. I will get back with a update.
Thanks again , I will give the Vit a try. Because I am frugal I used the Clays. It works very good in my other loads, it is very clean, it is cheap, and it requires 5o percent less powder and the paper I shoot at can't tell the difference. I will get back with a update.
Re: Temperature effect on pistol loads
If it's ejecting the fired case but not picking up a few round out of the magazine, it probably is underpowered to the point the slide isn't going back far enough to clear the next round and strip it from the mag. (I'm assuming you aren't "limp wristing" when you shoot it.)
A lot of semi auto pistols will eject on a weak round but not strip off a new one when the previous round is underpowered.
I've seen a lot of Bullseye shooters have the same problem. They are trying to find the borderline of just strong enough and the most accurate.
Good luck.
If it's ejecting the fired case but not picking up a few round out of the magazine, it probably is underpowered to the point the slide isn't going back far enough to clear the next round and strip it from the mag. (I'm assuming you aren't "limp wristing" when you shoot it.)
A lot of semi auto pistols will eject on a weak round but not strip off a new one when the previous round is underpowered.
I've seen a lot of Bullseye shooters have the same problem. They are trying to find the borderline of just strong enough and the most accurate.
Good luck.
Re: Temperature effect on pistol loads
No limp wrist. It strips the round out of the magazine but does not feed into the chamber all the time. When the gun itself is cold this adds to the problem. I am on my way to the range today and I will try some 180's that I loaded with Unique and IMR7625 as they are the same temp as the Clays round. I travel through Knoxville every time I go to Robbinsville NC. I like the Maryville and Tellico Plains area.
No limp wrist. It strips the round out of the magazine but does not feed into the chamber all the time. When the gun itself is cold this adds to the problem. I am on my way to the range today and I will try some 180's that I loaded with Unique and IMR7625 as they are the same temp as the Clays round. I travel through Knoxville every time I go to Robbinsville NC. I like the Maryville and Tellico Plains area.
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