Impact of cold on rimfire ammo

[slowworm]

So I was at the range today and was having very poor results wit my CZ-452. This has been a well behaved and well performing rifle in the past.

But today I was getting serious vertical stringing with Wolf Match Extra and less serious stringing with Eley Club. Last time out in the late summer I was getting decent groups. But today was 28F. Looking down the bore it looked like I had a bunch of unburnt powder lining the barrel, it was very dirty. The ammo is a few years old, but I've shot older stuff that this with no issues.

I can't say I've used the rifle in this cold before, so I was wondering if the issue may be temperature related?

It did occur to me when walking the dog I ought to check the stock screws as well.

Anyone have any thoughts?

 

[Tiger_Shilone]

There is a reason lapua and sk make polar biathlon ammo. Barrels get ”gummier” with sub zero temps, needs to be cleaned more frequently and extra elevation is needed. Using the polar ammo alleviates the gumming/cleaning issue from my experience. With that said I am out of it and still use center-x in lower temps knowing I need to make adjustments. Lube science is a thing with rimfire.

 

[45cal4life]

Had similar results few weeks ago with Center-X. Temp in the mid 20's and I purposely left the ammo outside overnight to ensure is was at ambient temp = Just use CCI SV and keep the ammo in a jacket pocket until early spring

 

[slowworm]

Thanks all. I guess I'll throw the ammo in an insulated lunch bag with a handwarmer when I'm at the range.

I'd like to try the polar biathlon ammo. I'm sure such expensive 22 match ammo is in stock ...

 

[brianf]

Regular Ammo = shotgun pattern in cold temps

I keep them in a inside pocket if I can’t get the cold weather stuff

 

[PPS LRPS.260]

I have had the same issues with alot of different types of ammo sk,lapua,eley,but what seemed to get better accuracy was the biathlon types, sk and lapua,i have my own theory,which is the lube is not as thin in colder weather which causes resistance in your barrel,along with the powder being colder, just my 2 cents

 

[walldog]

I've always wondered about what AFFECT cold has on ammo.

 

[Snuby642]

My gun likes cci sv.

Cci sv does not like cold.

Multiple magazines stored in a personal size cooler with small hand warming pack and a towel works for the range.

Inside of the coat is good but a hassle hunting with a semi auto.

 

[Tim7139]

This is pretty easy, at least relative to upper end ammunition.
Match ammo generally involves a good amount of nice warm lubrication that is on better ammunition being distributed down the bore.
This is why, even in warmer weather, it takes a few sighters to get proper lube throughout the bore and then things stabilize.
Below 40-45 degrees, that will not happen very well, lube won’t really distribute well. Biathalon ammo helps with it’s special lube but anybody looking for top flight results in winter weather......generally......ain’t gonna happen.

 

[barronian]

Thought this one might be of interest... three types of ammo shot in the same session, a few degrees above freezing and 'damp'..

No wind to blame anything on

100m prone
Sig Sauer STR 200
Delta 5-50x56
Rempel bipod and rear bag

The vertical on SK Pistol Match was caused by velocity spread. Similar to what i always see with Pistol Match.
Need to get a bit colder before Polar Biathlon shines.
The two fliers on the Eley Match were me

I was a bit surprised with this one since i often have problems with Eley Match under about 6degC.


Results with a CZ455 shot just after these were very similar.

All the ammo had been in the car for days - so they were at ambient temperature.
My experience has been that if it is under 8 degC and i take rounds from the house and start to shoot my way through them over an hour or two then I record much higher SD/ES - with any ammo type. If i let them cool first i get smaller SD/ES but im still looking for a round that works well just above freezing....

 

[JG26_Irish]

Interesting topic and one I was just telling a friend about. I shoot a lot of benchrest especially in the winter because my range has a range with the benches indoors and heated and we fire through portholes in plexiglass windows to outdoor tgts. We shoot at night and illuminate the targets so we can compete on weekdays. It is better than nothing but the cold messes with the ammo and the rifles. Here are couple of tricks that some shooters use to improve their scores:

1. Use the biathlon ammo if you can get it and it shoots well in your rifle. As stated above, the lube is different and the powder charge may also be different to compensate for the colder more dense air.

2. If it is near or at freezing, use a lot which is 2-3 meters/s slower. I use Lapua most of the time. If you are shooting 27 speed CX, try gearing down to 25 speed ammo. The ave velocity is roughly 6-7 ft/s slower. I have theories about why this may help which I will keep to myself since they are unproven. But it can help to stabilize the rifle in cold conditions.

3. Keep your ammo in the house where it is warm and when you go to the range, carry it in a small insulated bag or cooler with a hand warmer pack in there to keep it warm. Only remove the box you are shooting out of. This keeps the lube and powder warmer and may help. I am too lazy to do this and not quite anal enough to try it... Yet. Some of the most experienced and best shooters at my club do this and they are always the ones to beat. Others do not who are also still tough to beat. Does it help??? I do not know. I do plan to try it this winter though.

4. The cold messes with your rifle barrel. It cools quicker and powder residue condenses and coats the inner bore more than in warmer weather. The lube is less effective and I think lead fouling may increase due to that. Clean your bore more often and shoot more warmup foulers before you go to the target for score. When competing in summer, I shoot five foulers and two sighters and go straight to score in a match unless conditions (wind) force other tactics. In winter, I shoot ten foulers to better warm the bbl and then at least five sighters before I shoot a single shot for score. I also, try to keep a steady cadence and send about one shot every 30 sec. If I have to stop for wind, I will just keep shooting sighters until conditions warrant. This I do in summer and winter. It works for me.

5. Air is more dense in the cold. It's affect on your bullet will be more extreme in the cold. Spin drift may increase slightly at longer range shots and the bullet will slow quicker causing drop. But wind will also move the bullet more for the same speed of wind. So, if the wind picks up, stay aware of it and adjust accordingly. If you use wind flags or read mirage or movement of the foliage, and see change in the wind, let that be a red flag to stop, adjust and then send the shot. I shoot fast even in slow, timed BR matches. But in the cold, I do pay more attention to the winds.

 

[carbonbased]

Thought this one might be of interest... three types of ammo shot in the same session, a few degrees above freezing and 'damp'..

No wind to blame anything on

100m prone
Sig Sauer STR 200
Delta 5-50x56
Rempel bipod and rear bag

The vertical on SK Pistol Match was caused by velocity spread. Similar to what i always see with Pistol Match.
Need to get a bit colder before Polar Biathlon shines.
The two fliers on the Eley Match were me

I was a bit surprised with this one since i often have problems with Eley Match under about 6degC.


Results with a CZ455 shot just after these were very similar.

All the ammo had been in the car for days - so they were at ambient temperature.
My experience has been that if it is under 8 degC and i take rounds from the house and start to shoot my way through them over an hour or two then I record much higher SD/ES - with any ammo type. If i let them cool first i get smaller SD/ES but im still looking for a round that works well just above freezing....

What we see here, gentlemen, is obviously the machinations of that fiendish Rempel bipod, and decidedly not the fault of those poor little pills. To the trash!, I say, to the trash!




(best if read in a posh English accent, all the while clenching a pipe in one’s teeth – and do wear country tweeds!)

 

[slowworm]

I say old chap, aren’t you a tad harsh on the old fellow and his bipod? And that word trash, such a American term coming into common use. For heavens sake man, whatever happened to putting something into the rubbish bin!

To think what has become of the language of Chaucer and Shakespeare. It’s just not on old chap, just not on!

 

[545riflefan]

So I was at the range today and was having very poor results wit my CZ-452. This has been a well behaved and well performing rifle in the past.

But today I was getting serious vertical stringing with Wolf Match Extra and less serious stringing with Eley Club. Last time out in the late summer I was getting decent groups. But today was 28F. Looking down the bore it looked like I had a bunch of unburnt powder lining the barrel, it was very dirty. The ammo is a few years old, but I've shot older stuff that this with no issues.

I can't say I've used the rifle in this cold before, so I was wondering if the issue may be temperature related?

It did occur to me when walking the dog I ought to check the stock screws as well.

Anyone have any thoughts?

thank you for starting this thread. I’ve been wondering the same thing

today we finally got the chance to get out and see what the cold would do to our groups. 200 yards.

it was 28 deg outside. 84 % humidity and winds 6-7 mph

I’m pretty sure we can improve on these groups as the shooting benches had a layer of ice on them. Our bipods were sliding around so for sure we didn’t get a good position to shoot from. Anyway. It is what it is.

my wife and I both have Identical setup Tikka T1x’s. Sightron s3 6-24

I’m including an older set of targets from us for ref in judging the cold. ( id call these typical on how our Tikkas perform when it’s warm outside. )


we are shooting Lapua CenterX lot 2355184

the older ref picture has a 6x5 where we were comparing XAct to CenterX but it’s a great comparison for the cold.

I do think the groups opened up just a bit due to the cold but more so do to the iced bench.

with what we saw today we will go ahead with our plan to Lot test at Lapua using CenterX and Midas only. Until we shot today I was considering adding in the biathlon to the mix but don’t see the need for us as we rarely shoot in the weather this cold.

 

[545riflefan]

Forgot to add that we had to dial an additional 9 MOA of elevation due to the cold. I’m normally 23-24ish MOA at 200 when the temp is around 70 deg.

today with the temp at 28 deg I had 32 MOA of elevation dialed in.

 

[545riflefan]

Got out again today as the ice melted off the benches. 36 deg. Winds 2-3. These are posted in the 6x5 thread but wanted to put them here also as they are all about how the cold has an impact on the performance

overall I’m pretty happy with the way the CenterX is performing in the cold.

 

[Tiger_Shilone]

Got out again today as the ice melted off the benches. 36 deg. Winds 2-3. These are posted in the 6x5 thread but wanted to put them here also as they are all about how the cold has an impact on the performance

overall I’m pretty happy with the way the CenterX is performing in the cold.

If that is more 200 yard testing I am impressed as you are seeing the mv spread difference with small wind variances. Nice shooting!

 

[545riflefan]

If that is more 200 yard testing I am impressed as you are seeing the mv spread difference with small wind variances. Nice shooting!

thank you very much. I forgot to mark the targets to show the distance they were shot at before I took the pic. They are now marked . Yes it was at 200 yards.

 

[jbell]

Over the years I have noticed the same thing, when air temps drop below 40f the razor edge of accuracy slightly degrades at the freezing point and just below it is slightly worse with noticeably less consistency and when the mercury is in the low 20’s or below all bets are off for real accuracy. Now this is not to say that your rifle will shoot like a smooth bore musket or anything but if you have a top level shooting rifle and ammo combination generally don’t expect the same accuracy as if it were a warm day. As mentioned a winter specific ammo definitely helps some, Lapua Polar and Eley Biathlon are both good choices. But even with a select lot I haven’t seen accuracy restored to the same level as when it is warm.

One more thing I notice in the extreme cold is the wind will have a larger POI shift than it does when it is warm out. Not drastic mind you, but enough to make me take notice.

 

[barronian]

i was trying to test a theory yesterday ... now i'm much colder and not much wiser

-3 C ambient temp with Eley Match that had been left out overnight at -3.
the theory was that if i shot say 4 rounds rapidly then left the 5th round in the breach for a while before firing would the 'warm' breach change the powder temp and hence change the velocity....

the answer was yes - sort of , maybe, but not consistently ?
The 'warmed' up round would often have the expected higher velocity but not always..

more testing needed.

anyone have an input to this idea ?

 

[Tim7139]

i was trying to test a theory yesterday ... now i'm much colder and not much wiser

-3 C ambient temp with Eley Match that had been left out overnight at -3.
the theory was that if i shot say 4 rounds rapidly then left the 5th round in the breach for a while before firing would the 'warm' breach change the powder temp and hence change the velocity....

the answer was yes - sort of , maybe, but not consistently ?
The 'warmed' up round would often have the expected higher velocity but not always..

more testing needed.

anyone have an input to this idea ?

when it is cold, the single biggest variable to consistency is the difficulty in maintaining any stable viscosity of bullet lube that needs to be distributed uniformly throughout the entire bore.
this, the primary reason once temps fall below, around 40deg or so, any gun will not perform at it’s optimal level with any consistency....if at all.

 

[Outdoors]

i was trying to test a theory yesterday ... now i'm much colder and not much wiser

-3 C ambient temp with Eley Match that had been left out overnight at -3.
the theory was that if i shot say 4 rounds rapidly then left the 5th round in the breach for a while before firing would the 'warm' breach change the powder temp and hence change the velocity....

the answer was yes - sort of , maybe, but not consistently ?
The 'warmed' up round would often have the expected higher velocity but not always..

more testing needed.

anyone have an input to this idea ?

i have observed the same thing starting about 45F and getting worse at 35F. Some rounds, but not all, will drop an MOA or more at 100 yds. This is without trying to keep anything warm. Seems like something a bad scope would do. If i keep the ammo warm, it will be consistent. Warm in my case is heated in doors, step out to back patio in the cold and shoot immediatly. Once the ammo is cold, some rounds will shoot low and others will not. I would guess at some temperature, it would become consistent again. Big problem here is 25F in the morning then 45f afternoons. Ammo seems to go crazy in that temperature band.

 

[PlinkIt]

So who's going to be the first one to hook a battery up to a barrel as a warmer?....

 

[Outdoors]

LOL -Wonder if a car battery would count as ”one piece of equipment” in nrl22. Starts with all equipment in hand could be tricky.

 

[Booner1334]

LOL -Wonder if a car battery would count as ”one piece of equipment” in nrl22. Starts with all equipment in hand could be tricky.

Instead of hooking up a battery to the barrel, how about taping a bunch of hand warmers to it?

 

[grauhanen]

i was trying to test a theory yesterday ... now i'm much colder and not much wiser

-3 C ambient temp with Eley Match that had been left out overnight at -3.
the theory was that if i shot say 4 rounds rapidly then left the 5th round in the breach for a while before firing would the 'warm' breach change the powder temp and hence change the velocity....

the answer was yes - sort of , maybe, but not consistently ?
The 'warmed' up round would often have the expected higher velocity but not always..

more testing needed.

anyone have an input to this idea ?

It may be that one of the problems of shooting in colder temperatures is that a bolt action .22LR doesn't really heat up the barrel or chamber area to any significant degree. There are few scientific studies of temperature changes in a .22LR barrel from shooting, but there is one study done at room temperatures that shows the following conclusion after 40 shots taken at the rate of two shots per minute with a Walther KK300 rifle.

The rifle barrel external temperature increased mainly in its near-lock area (up to 5°C). With growing distance from the lock the increase in temperature is lower and it is just 1.5°C at the end of the barrel.

EXTERNAL BARREL TEMPERATURE OF A SMALL BORE OLYMPIC RIFLE AND SHOOTING PRECISION (nih.gov)

The temperature increase would be greater inside the barrel, but the point is that there's simply not a lot of heating going on, and this is especially more pronounced down the barrel.

An important factor in cooler temperatures is maintaining consistent lube characteristics. When barrels are cold lube/fouling can be inconsistent. Eley Tenex Biathlon and Lapua's new Biathlon Extreme use a lubrication that is different from their other .22LR ammos in an effort to mitigate the problem.

Of course the simple answer to the problem of shooting in colder temps is using ammo made for biathlon. But the simple answer would be wrong because like every match ammo, results aren't guaranteed to be good because of the name on the box of ammo. Biathlon ammo is subject to the same lot vairation as other .22LR match ammo. No one can guarantee that simply by shooting random lots of Lapua X-Act will ipso facto produce better results than Lapua Center X. Biathlon ammo must be tested by lot just as any other ammo.

 

[BillW73]

My shooting temps during the year are from on average, mid 60s to about -20. However thanks to global warming, the last couple of winters have rarely gone below 0.
I shoot a 40X and a 52B. I use Eley Match and Club. I shoot out to 100 yards.
I see no change on my targets from the 60s down to about 32 deg. I take no special care of my ammo as far as the temp goes. I set it on the bench and leave it there until I am done, no matter how cold it is.
Now once it gets down into the low 30s I start to notice a change on my first couple of rounds. After about 5 shots it settles down, and starts hitting right where it is supposed to. As long as I continue to shoot my results are what I expect. However if I stop, for target changes or just to go warm up I have to start the whole fouling process over again.
Once the temps get into the teens and lower it takes more fouling shots to get the rifle shooting how it is supposed to. The interesting thing is that I have found that I can use any ammo for the fouling shots. For the longest time I was using the Eley for this, then I decide to try using some Blazer. I fired 5 rounds of Blazer, than 2 of the Eley, and I was right where I wanted to be. I have come to the conclusion, for right or wrong, that what matters most is what is going on in the barrel, not necessarily what temp the ammo is.
I shoot for fun so using the extra ammo to warm up the barrel is no big deal. That would not work in a match. But no matter what, my accuracy does not change enough that I can not take head shots on ptarmigan.
I have also come to the conclusion that once the temps get in the teens or lower that me being cold is the biggest issue with accuracy.

 

[BushyAR15]

My rifle tends to shoot about .2 mil high when the temps are cold meaning around 32-40 degrees F. At about 50 degrees it's consistent again and where I zeroed. Very good info in this thread that I didn't know!

 

[barronian]

@Tim7139 @Outdoors @grauhanen @BillW73 well you got me thinking... so i went out and experimented a bit further today - a colder day today (-8C 17F ) so i could get another datapoint. I still see a statistical correlation between decreasing temp and decreasing velocity but the variability (SD) still results in a very high percentage of 'noise'.
@Tim7139 comments brought me back to something that i had been investigating during the summer - humidity effects in the barrel. Well, i can categorically state that for my gun @Tim7139 is absolutely correct - lubrication effects can be an order of magnitude greater than the temp effects

So what i did to change the in-barrel friction parameters was to blow down the barrel ... In summer this produces a humidity film on the inner surface - at -8 it produces a very thin ice layer.

In very rough numbers i see :
Temperature sensitivity about 3 ft/s change per degC
blowing once down the barrel dropped the velocity c. 33 ft/s
blowing 3 times down the barrel dropped the velocity c. 90 ft/s
blowing 4 times down the barrel dropped the velocity c. 116 ft/s

I repeated this several times with several normal shots in between each "blow job"
Interestingly the blowing only effected the shot directly after the blowing - a second or third shot were back up to normal velocities.

Unfortunately this doesn't help us predict or mitigate the lubrication variability but i t does appear to confirm that it exists and that the magnitude could be quite high.

so now we need to test a super slick coating that is unaffected by the shooting conditions in a barrel ... (back to something like molly - but better? )

The paper that @grauhanen linked to was very interesting. My warming shots were shot at a much faster rate and, provided i can extrapolate the test results to my gun, would have resulted in approx only 1.5degC max warming. Moreover, it looks like the max warming was (logically) well in front of the chamber so my theory of a hot chamber warming the powder really isn't supported at all ...

 

[Tim7139]

@Tim7139 @Outdoors @grauhanen @BillW73 well you got me thinking... so i went out and experimented a bit further today - a colder day today (-8C 17F ) so i could get another datapoint. I still see a statistical correlation between decreasing temp and decreasing velocity but the variability (SD) still results in a very high percentage of 'noise'.
@Tim7139 comments brought me back to something that i had been investigating during the summer - humidity effects in the barrel. Well, i can categorically state that for my gun @Tim7139 is absolutely correct - lubrication effects can be an order of magnitude greater than the temp effects

So what i did to change the in-barrel friction parameters was to blow down the barrel ... In summer this produces a humidity film on the inner surface - at -8 it produces a very thin ice layer.

In very rough numbers i see :
Temperature sensitivity about 3 ft/s change per degC
blowing once down the barrel dropped the velocity c. 33 ft/s
blowing 3 times down the barrel dropped the velocity c. 90 ft/s
blowing 4 times down the barrel dropped the velocity c. 116 ft/s

I repeated this several times with several normal shots in between each "blow job"
Interestingly the blowing only effected the shot directly after the blowing - a second or third shot were back up to normal velocities.

Unfortunately this doesn't help us predict or mitigate the lubrication variability but i t does appear to confirm that it exists and that the magnitude could be quite high.

so now we need to test a super slick coating that is unaffected by the shooting conditions in a barrel ... (back to something like molly - but better? )

The paper that @grauhanen linked to was very interesting. My warming shots were shot at a much faster rate and, provided i can extrapolate the test results to my gun, would have resulted in approx only 1.5degC max warming. Moreover, it looks like the max warming was (logically) well in front of the chamber so my theory of a hot chamber warming the powder really isn't supported at all ...

RE you’re humidity experiments.....you don’t need to blow down the barrel.
if you shoot ELEY in particular( what I have most experience with), try this.
Run a few shots down the barrel and then, within a minute, run a clean, dry patch and touch it to your lips. You’d be surprised how wet that patch feels to the touch.
this is one reason lots of BR shooters, at a minimum, run a patch or two after every card to hit that lube while it is warm/moist, quickly after shooting..
22 rifle shooting generates a fair bit of water vapor as a by product of combustion......try it.

 

[barronian]

@Tim7139 i can give it a go tomorrow

 

[Outdoors]

@barronian What ammo are you doing your humidity tests with? SK seems to suffer the most in the cold to me. @Tim7139 mentioned his observations with Eley. In my experience, Eley while it dropped speed, is more consistent than SK in cold. I prefer SK in the warmer weather.

 

[Tim7139]

@barronian What ammo are you doing your humidity tests with? SK seems to suffer the most in the cold to me. @Tim7139 mentioned his observations with Eley. In my experience, Eley while it dropped speed, is more consistent than SK in cold. I prefer SK in the warmer weather.

well, to be honest, not really even my observations.
I realize there really not a population of sanctioned BR shooters over here but this whole cold weather ammo deal has been universally known and accepted in that community....the principle reason all sanctioned matches end anywhere it gets quite cold. More than a couple smiths also caution about bore leading as a result of insufficient bullet lube, etc.a whole other issue, many do not effectively handle without risk of bbl damage.

 

[ma smith]

Just reading the above post about dry patch
coming out with some kind of moisture

Curious if moisture condensation INSIDE
the barrel messing also messing with shots?

 

[Tim7139]

Just reading the above post about dry patch
coming out with some kind of moisture

Curious if moisture condensation INSIDE
the barrel messing also messing with shots?

understand, My statement was in no regard having anything to do with cold weather.
Run the same test when it’s 90deg.....same wet patch. It is simply a by product of 22 combustion/bullet lube.
Also understand, the front edge of that drive band does a great job of pushing fouling & excess lube out the bore, leaving nice uniform film behind......not happening well in the cold.

 

[ma smith]

understand, My statement was in no regard having anything to do with cold weather.
Run the same test when it’s 90deg.....same wet patch. It is simply a by product of 22 combustion/bullet lube

Is the "wet" h20 liquid or some other liquid?
This is new to me so just curious to understand.
Cheers

 

[Tim7139]

Is the "wet" h20 liquid or some other liquid?
This is new to me so just curious to understand.
Cheers

other liquid??? Maybe single malt scotch
Unless they secretly stuff a single miniature blueberry in there, I think we’re safe with water vapor.

 

[ma smith]

Now in the cold, we think about what's going on with condensation.
Dew points, thermal gradients, humidity gradients, etc

Prob is h20 in the barrel is hydraulic medium,
gonna mess with runnign surface of bore, inconsistent, etc

Or am I not following this where you were going?

 

[StrayDog]

I couldn't find Lapua Biathlon few months ago, but I found some SK Biathlon.

Our December NRL22 was in the low 40s and the SKB shot as well as my Center X, but this weekend our January COF will be 30 degrees top.

Gonna shoot some strings before we start at 100 to see how it goes and warm up a bit.

Who knows, if we start the 55 gallon drum firepit, maybe I'll keep the ammo close to it, but not close enough to melt those Vudoo mags!

 

[Calfed]

I started shooting in an early morning .22 target match every Tuesday morning. Recently the weather has turned colder (about 35F) and I noticed a fall off in my scores using my usual Lapua Center -X.

I had 4 boxes of Lapua Polar Biathalon and switched over to using it. I noticed a marked improvement over the Center-X. I also started putting a hand warmer in my ammo box, which seemed to help a bit.

These have been my results for the last two weeks (match distance alternate between 50 yards one week and 100 yards the next)

This was last week, 10 rounds Polar Biathalon at 100yards-.945" with a Winchester 52D/B&L 6-24 x 40

Today I was using a Martini International MK V at 50 yards/Lyman 20X STS. Five rounds of L. P.B. in each target.

 

[Calfed]

Anyone consider using a cordless heat gun to heat the barrel/receiver before shooting the rifle?

20V MAX* Cordless Heat Gun Kit

Go places your corded heat gun can't. This 20V MAX* cordless heat gun is compact for use in tight spaces and diverse applications, including heat shrinking wire tubing and paint and decal removal. It features up to a 990° max output temperature** and comes with two temperature settings. The...

www.dewalt.com

 

[barronian]

@barronian What ammo are you doing your humidity tests with? SK seems to suffer the most in the cold to me. @Tim7139 mentioned his observations with Eley. In my experience, Eley while it dropped speed, is more consistent than SK in cold. I prefer SK in the warmer weather.

I mainly use Eley Match but I've played around with 17 different round types. SK pistol Match Special was the only SK round type that worked well for me.

 

[barronian]

Assumptions:

1. The water vapour produced by the combustion of the propellant will condense in the barrel
2. This water condensation will change the coefficient of friction of the barrel
3. The water vapour will act as a retardant to the combustion of the propellant (cf. http://bulletin.accurateshooter.com/2018/03/humidity-and-powder-burn-rates-what-you-need-to-know/ )

Observations:
2. I dont know what the net effect is above freezing, but below freezing it definitely retards the bullet (see my earlier post)
3. This might explain why the first round in a session is often 'hot' - the barrel is dry coming from the house before the first round is fired ?

 

[carbonbased]

Some of my best friends are retarded bullets.

 

[barronian]

Continued testing temperature effects....
Preliminary results ! - only one gun and a couple of hundred data points.

Tried all combinations of three different gun temperatures and 3 different bullet temperatures
ie 24 degC gun and 24C, 0C and -6C bullets/powder
0 degC gun and 24C, 0C and -6C bullets/powder
-6 degC gun and 24C, 0C and -6C bullets/powder

looks like there is approx 3 ft/s change with 30 degC change in bullet/powder temp
and approx 25 ft/s change with 30 degC change in gun temp (same bullet/powder temp)

ie if both the gun and bullet/powder change 30 degC (86F) then i see only a 28 ft/s change in velocity.

It was interesting to learn that (for my gun ) the temp of the gun was more important than the temp of the powder. I would also have thought that a colder (tighter) barrel and chamber would have been faster - instead it is slower. Suggests that the barrel is pretty 'tight' even when it isn't frozen.

 

[Tim7139]

Continued testing temperature effects....
Preliminary results ! - only one gun and a couple of hundred data points.

Tried all combinations of three different gun temperatures and 3 different bullet temperatures
ie 24 degC gun and 24C, 0C and -6C bullets/powder
0 degC gun and 24C, 0C and -6C bullets/powder
-6 degC gun and 24C, 0C and -6C bullets/powder

looks like there is approx 3 ft/s change with 30 degC change in bullet/powder temp
and approx 25 ft/s change with 30 degC change in gun temp (same bullet/powder temp)

ie if both the gun and bullet/powder change 30 degC (86F) then i see only a 28 ft/s change in velocity.

It was interesting to learn that (for my gun ) the temp of the gun was more important than the temp of the powder. I would also have thought that a colder (tighter) barrel and chamber would have been faster - instead it is slower. Suggests that the barrel is pretty 'tight' even when it isn't frozen.

FWIW it suggests nothing of the kind, what it suggests is the lube stays harder and thus slower because of more resistance.
You can play with this until the end of time but the simple truth is bullet lube working less than designed as a result of cold but variable weather will never change. About the only other variable is shot timing....i.e. quicker is somewhat softer.
I mean, why come up with wild, speculative, assumptions when the simple, logical , and frankly, proven explanation is staring right at you ?

 

[Rover31]

@barronian
some may sigh at my post here as I have mentioned this many times over the years... happy to do it again for those who have not read my ramblin.

I have done extensive testing with 22lr rifles and temp variation over the years.
my findings are that once you are shooting “quality” ammo the rifle barrel quality and cold sensitivity play a larger role than the ammo. Some barrels are effected by the cold more than others. This variable will then show the difference in ammo “quality“ at a greater level, ie larger or smaller groups. The barrels that are less effected by cold are consistent in groupings at all temps. Thus higher “quality” ammo shows better results.

so how that translates for me is, My daughter then shoots polar ammo in her 1827f only once conditions are at 15f +/- a few degrees depending on the humidity levels. Even then until you are at the world circuit level it is not necessary.

 

[barronian]

FWIW it suggests nothing of the kind, what it suggests is the lube stays harder and thus slower because of more resistance.
You can play with this until the end of time but the simple truth is bullet lube working less than designed as a result of cold but variable weather will never change. About the only other variable is shot timing....i.e. quicker is somewhat softer.
I mean, why come up with wild, speculative, assumptions when the simple, logical , and frankly, proven explanation is staring right at you ?

@Tim7139 OK, i can live with that as a working explanation
@Rover31 makes sense - i just had to prove to myself that the effect was real, its magnitude and get an idea of what causes it. Having SOME knowledge of my own makes it much easier to filter the 'wisdom of the net'

 

[barronian]

@Tim7139 have you any experience of comparing 'de-waxed' bullets to their waxed form ? Or would de-waxed bullets cause excessive galling ?

 

[Tim7139]

@Tim7139 OK, i can live with that as a working explanation
@Rover31 makes sense - i just had to prove to myself that the effect was real, its magnitude and get an idea of what causes it. Having SOME knowledge of my own makes it much easier to filter the 'wisdom of the net'

Perfectly understandable. I deserve zero credit for any of this.
If you have been a devotee of BR methods and technology ( I use BR because it has been a leader in gunsmithing, components, barrel development for some years) this has been pretty widely appreciated and tested by world class gunsmiths, and shooters. ELEY themselves have, in the past, stated same.