The cold weather always knocks about 10 shots off the usable shot count on my AA S200 and S400, plus my BSA Scorpion.
Hi all
Since the weather has turned more wintery in the last few weeks and going forward it seems that this is having an affect on air rifles, especially the shot count. And comes up in discussion at the range with differing ideas.
This seems to affect different rifles different amounts though. For example my HW100 KT seems to be effected quite a lot, down beyween 15-20 shots. Where the Daystate Wolverine B is not so much effected, down by roughly up to 10 shots on average. Other people's rifles also differ dependant on make and model.
The temperature also seems to have an affect on the mil dot range when aiming. The colder it is the more mil dot adjustment needed to hit the target. This however seems constant over the rifles that I own.
Can anyone provide some info on why this happens? Is it due to pressure drop and if so, why is the mil dot change not changing different for each rifle in a similar way to the shot count?
Any idea gratefully received, along with pointing out something that is obvious I have missed totally (which would not be unheard of ).
Thanks
Ross
The cold weather always knocks about 10 shots off the usable shot count on my AA S200 and S400, plus my BSA Scorpion.
Last edited by Trumpetier; 05-12-2016 at 06:07 AM.
It will have a lot to do with grease
I'm sure I've read on this site previously that it's to do with the density or something of colder air. I'm sure the grease theory is relevant, but I stripped my S400 a few years ago, as I'd herd about the grease on the hammer rail theory, but it made no difference to my 400. In the summer all my PCP, s give more shots and slightly higher power readings.
Definitely grease on springers makes a difference in the cold winter months.
I have lost 10 shots with my KT 100 which is about the norm for PCPs. No grease in the shuttle and hammer mechanism. This was washed out long time ago and I keep it lubricated by squirting some airgun oil over the mechanics from time to time.
I am not sure if the cold has anything to do with increasing the accuracy of the gun but yesterday morning while zeroing the the rifle at my outdoor club the gun printed 1/4" pattern with 5 shots at 55 yards using jsb 4.53s out of a bug standard tin. Four pellets went in the same hole and one slightly low and left otherwise it would have been one hole. I have never been able to achieve that kind of accuracy with the gun before even while shooting indoors let alone outdoors. It is usually sub 1/2" at 55 yards.
A.G
It will be the combined effect of many microscopic changes;
Almost every type of lube will be thicker & stickier when cold, a bottle filled inside a warm house will drop pressure as the air inside cools & contracts, metal rifle components will also cool & the metal will contract fractionally so sliding components may be a tighter fit, including the pellet in the barrel & cold damp air is denser than warm dry air so will effect the pellet in flight.
Funny that, the cold weather hasn't knocked anything off the shot-count of my 99s. Maybe it's just the rifles you lot are using..
Are losin' control...
(Somebody had to do it).
Too many guns, or not enough time?
The main problem is you are filling the gun at your house, where the air is nice and warm.
Get to the permission, where it is nice and cold and that gas in the cylinder contracts, it shrinks, so your shot count will go down. This could also affect your POI.
My 100kt is about one magazine down on shot count this weather but, POI isn't affected until it gets in the 'yellow' on the guage as per any time of year.
HW77K .22, HW100KT .22, HW95K .22. AA TX200 MK3 .22. AA S410 MK3 .177. HW80 .25 HW30S .22. Pistols: Walther CP88 .177, Hatsan Mod25 Supercharger .22, HW45 Silver Star .177, Webley Alecto .177, SMK Victory CP2 .22