Zeroing a 22 in cold vs warm hot weather. 30’s or 80-90’s

[Bgriff008]

Just curious when most of you zero a 22 PRS rifle. In cold weather or hot.

I’ve made it a point to zero in cold weather, like in the mid 30’s degree F. At that temp my Sk+ and SKRM ammo shoot at its slowest FPS. Right at 1074fps as indicated on the box at 50 yards. In 90 degree temps my MV is 1106fps. That’s a 30fps swing. My thought process in this is as temps increase of course the MV increases and will always be above my scope zero. As opposed to zeroing in summer temps and having to dial my scope down past my zero setting. But I’ve never really tested my theory. Does anyone have any experience or have witnessed any affects for which I am thinking?

 

[CNC-Dude]

Well, the temps can and do affect your Zero. But the humidity and density altitude play a part also. Cold weather with low humidity vs. high humidity can affect it as much as the hot vs. cold scenario....

 

[Bgriff008]

Well, the temps can and do affect your Zero. But the humidity and density altitude play a part also. Cold weather with low humidity vs. high humidity can affect it as much as the hot vs. cold scenario....

Here in Ohio MV appears more affected by temp. But I admit humidity increases with the temp so it all affect it. I just have preferred to site in when I have found my MV at its lowest. The nice thing with the Kestrel is the MV temp settings. This dials in the dope nicely with temp changes. Cool mornings with warmer afternoons.

 

[B y r o n]

How about zeroing it at the temperature that it gets shot the most. Seems like you would be tinkering less.

 

[Emerson0311]

Just curious when most of you zero a 22 PRS rifle. In cold weather or hot.

I’ve made it a point to zero in cold weather, like in the mid 30’s degree F. At that temp my Sk+ and SKRM ammo shoot at its slowest FPS. Right at 1074fps as indicated on the box at 50 yards. In 90 degree temps my MV is 1106fps. That’s a 30fps swing. My thought process in this is as temps increase of course the MV increases and will always be above my scope zero. As opposed to zeroing in summer temps and having to dial my scope down past my zero setting. But I’ve never really tested my theory. Does anyone have any experience or have witnessed any affects for which I am thinking?

My SK S+ and SKRM show about 1030fps at 6C. SKLRM is 1068. Verified via drop at 275M, while zeroed at 47M. I sure as fuck hope they speed up in the heat of summer. Same velocities in stock T1Xbarrel and 12T IBI. Higher humidity pushed SKS+ down to 1000fps over a chrono. Eley seems to maintain 1070-ish when much above freezing. I’ve got a lot of SK, and budget limitations so it’s what I shoot.

 

[Bgriff008]

How about zeroing it at the temperature that it gets shot the most. Seems like you would be tinkering less.

I don’t tinker at all. Just saying once it’s zeroed in the cold weather, I leave it. The kestrel makes the necessary adjustments as temps increase. But the gun is dialed in at all temps. I like knowing that my zero is at lowest MV and I only need to go past zero is for shots at less than 50.

 

[Bgriff008]

My SK S+ and SKRM show about 1030fps at 6C. SKLRM is 1068. Verified via drop at 275M, while zeroed at 47M. I sure as fuck hope they speed up in the heat of summer. Same velocities in stock T1Xbarrel and 12T IBI. Higher humidity pushed SKS+ down to 1000fps over a chrono. Eley seems to maintain 1070-ish when much above freezing. I’ve got a lot of SK, and budget limitations so it’s what I shoot.

Wow I can’t ever recall seeing My SK ammo below 1060fps. Again I haven’t shot it below mid 30’s degree F. But 6 degree C is about 42 deg F. Man that seems way slow for Sk+ or RM. maybe it’s your location.

 

[DFOOSKING]

I don't see how if your concerned about it that much....

1. You just check zero frequently or shoot practice/training groups to reassure yourself of its POI.

2. You are or aren't shooting enough that you actually need to check zero. If you shoot all year frequently....you should be burning up lots (manufacturing lots...) forcing you to recheck zero often. Or you don't shoot it all that much so why aren't you spending the 10 rounds for the rare occassion/session to check zero as needed.

This is not meant to sound as an attack on you. I'm just saying or trying to say simply that it is not a concern for most people because if they compete....they are constantly forced to stay on top of their zero through the year.

And if you aren't checking zero often.....your targets/quarry are big enough to let you get by without chasing it. Which i totally get. My truck gun will easily dome a rabbit or squirrel at 25-45yds year round. And I shoot it enough to see for example the 100yd sight setting shift about 1.5 moa (0.4 mils) from hottest day to the most mind numbing frigid. That application allows for some wiggle room as a +100yd cottontail taking one center mass will give it.

My NRL22 match rifle that needs to hit that stupid .25" spinner at 25yds does not. I shoot a brick to two bricks a month when I really hopping match to match there for a while. So production lots changed all the time.

Obviously, the guy who shoots a lot stays on top of his zero and easily enough observes the trends his ammo exhibits. To which they make a mental note or log it.

Every serious competitor will check zero just to be sure nothing bumped the gun off in transport or I've personally seen plenty who forget to return to zero and catch it at sight in prior to the match.

 

[Vamike9]

Just curious when most of you zero a 22 PRS rifle. In cold weather or hot.

I’ve made it a point to zero in cold weather, like in the mid 30’s degree F. At that temp my Sk+ and SKRM ammo shoot at its slowest FPS. Right at 1074fps as indicated on the box at 50 yards. In 90 degree temps my MV is 1106fps. That’s a 30fps swing. My thought process in this is as temps increase of course the MV increases and will always be above my scope zero. As opposed to zeroing in summer temps and having to dial my scope down past my zero setting. But I’ve never really tested my theory. Does anyone have any experience or have witnessed any affects for which I am thinking?

I've actually tested this to a small degree, in 27deg and 60+deg temps, no noticeable 50yd zero shift.
I even left the ammo outside overnight with 20deg temps, shot it the next day and it went back in the same 60deg zero (50yds).
There are always other factors that can come into play, however, I've found most quality ammo to be pretty temp stable with my Bergara B14r.
I have a video that I was gonna post about this test, but ended up doing other things.
Hope this helps you on your journey.

 

[M4orturnate]

Also in ohio and shoot all over the state and Pa mostly. I usually have to adjust my zero from match to match. Typically 5 rounds for that( nevet more than 2 tenths) and 10 rounds to chrono is my usual warm up. Ive gone from west OH to midish Pa and zero needs up to .4. Probably could have just ran the match but the spinners would give me shit

 

[Bgriff008]

Excellent advice. Thanks everyone. I will be trying to check my zero as often as I can before a match. They usually let anyone that wants to, zero at the range just before the match. I shot a match this past Sunday @60 degrees and zero was spot on. Last I zeroed was in February when temps were mid 30’s. But I think I will check it before a match just to be sure. Oh. I am also shooting a Bergara B14.

I would think in the summer when the ammo is over 1100 fps the 50 yd zero would be definitely affected more.
As for picking lots, well, I don’t get caught up in lot testing. The Sk+ and SKRM are pretty consistent out of my gun. But I will at least try to zero when I open a new brick.

As for frequency of shooting, I wish I shot more matches. Our range has 4-5 PRS matches a year. And I have yet to venture to any other PRS match outside the range or state. I definitely would benefit from more match time.

 

[obx22]

Editing:
Stop. I’m second guessing my statement based on starting zero. If you zero at 40F, then on match day it’s 80F, you may need a different starting zero, I’ve got to ponder this. I start with a parallax limited 15yds, my friends all ask why as they start at 50yds. Today I began to wonder if a long range zero would be more precise at all distances?
Forgive me as I’d hate to give bogus info.

(Irrelevant as it’s just a factor entered into the conditions of the day. Right now I’m blessed, my target load is say 1076 when it’s 76 degrees, 1052 when it’s 52 degrees, etc. The ballistic app takes those factors into account and spits out the dope for present conditions, not what it was when I zeroed.)

 

[Emerson0311]

My SKS+ velocity goes from 989fps at -2C, to 1040fps at 12C. I zero morning of whenever a shoot matters.