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Barrel "warm up"

3K views 16 replies 17 participants last post by  BadgerJack 
#1 ·
Realizing that there are different opinions but just asking what some of them are. In an attempt to save on the "good ammunition" is there an advantage or disadvantage to using a "lesser" ammunition to warm up with prior to shooting for score? If doing that, do you swab the bore prior to changing ammunition then shoot some seasoning rounds?
 
#5 ·
I don't think there is an advantage. Maybe even a disadvantage.

The bullet going down the barrel now is riding on the residue left behind by the previous bullet.... including the lube which is a big part of the difference between the high-dollar ammo and other loads.
:yeahthat:
 
#4 ·
I am not familiar with all ammo within an individual brand, but for what I am familiar with, Lapua uses their own lubricant. So as long as you warm up using a lower cost Lapua, you should be OK to move up to a higher performance Lapua without a problem. The same would be true for Eley. For example: warm up with Lapua Standard Plus and then shoot with Lapua Midas. The problem mostly comes when you "cross contaminate" by warming up with one brand and then switching brands. For example: warming up with Lapua Standard Plus and then switching to RWS R50. Burt
 
#7 ·
Assuming we are talking about "heavy" match barreled guns.
Assuming the sole reason for "warming up the barrel" is that the steel reacts to the temperature increase by moving in some direction;
Is anybody aware of any engineering studies conducted with how much the muzzle move per degree/ of temperature rise? This could be done with dial indicators,, thermocouples, etc.
Questions that my engineering can't help asking:
How much does the barrel temperature increase per fired round?
How much does the muzzle move based solely on temperature increase?
At what temperature increase/round count does the barrel stabilize?
Does the barrel stabilize?
What is the frequency of fire required to maintain the "perfect" temperature?
If you fire too fast or frequently can you exceed the temperature for a stable barrel, leading to tube droop, as we called in my Army Tanker days?

Or maybe we should shoot the engineer and just enjoy shooting!:beerchug:
 
#9 ·
Well I used to shoot the cheap ammo first and then th better ammo. But one day, being cantankerous, i switched and shot the betterammo first. Not only were the better ammo groups better, so were the cheap ammo groups too! I think that greasy lube on the better ammo makes the cheaper ammo shoot better. And for me the first groups always are best.
 
#12 ·
barrel warm up

Barrel temp does matter. it is a big factor with match accuracy wit 22 rf barrels
(I have no experience with the jacketed bullets used with 22WRM or the 17s)
I've shot 22 rf benchrest (ASSRA Matches) for years. We shoot outdoors, from early spring to late fall, in bench matches at 100 and 200 yards with the best ammo money could buy. Early or late in the season, on the range in northern Indiana we could have 1st relay matches with temps you could see your breath in and at 2 or 3 in the afternoon temps might be pushing 70 or more. In a few memorable early spring match we had snow on the ground and snow in the air.

the film of waxy lube coating the lands and the grooves is highly subject to temperature----think of your butter dish in your kitchen--impossible to spread fresh from the fridge and a puddle impossible to spread on a hot day with no AC. Pushing a bullet down a cold barrel REALLY slows the bullet down----even of the best ammo. Once the barrel has warmed up and the lube coating is softer and slicker it'll travel a lot faster.

With my heavy barrel (30"x1 1/2" octagonal) 200 yard benchrest 22 rf, out of a cold barrel, the bullet would hit close to a foot low on a cold windless morning. at 100 yards the drop would be less of course. My other match rifles with less mass-weight barrels would heat up and also cool back down faster.
Normally I'd just keep shooting on a sighter target and watch the bullets "walk" up and over the the impact point for that sight setting. the number of shots would vary depending on conditions.
I always wanted to get some sort of stick on temperature sensing pads hooked to a device that would let me calculate the temps as i was going through the process. but never did.

Changing ammo brands just adds a whole bunch of unknown and inconsistent factors due to the differences in lube mixture and application. Even changing match ammo brands required cleaning all the lube out of the barrel and re-lubing by firing the different ammo until the barrel was re-lubed. A rule of thumb most of us used was as that in a squeaky-clean un-lubed barrel each shot would grease about 3-4 inches of barrel----you could see the groups shift and tighten as the re-lubing progressed.

I did find that Bi-athalon/Winter 22 match ammo worked better-- I think the lube must be adjusted to have a functional lubricity wider range of temperature but its more expensive of course.
We shot a 45 min relay with a 15 min break to pull and post targets. Even with mu rifles warmed up I learned to use chamber and muzzle plugging Safety "flags" to help the barrel hold its temperature on cooler days It would drop some and take four or 5 shots to get back-up to "accurate temps". but a lot longer if I waited out a relay or forgot to plug both ends.

Barrels mass and ambient temps will vary, as will different brands and types of ammo. Off hand I'd say that on "normal comfortable" shooting temps say 60-80 or so that temperature won't have that big factor. I routinely started every relay with half a dozen shots onto a sighter target
 
#15 · (Edited)
Re: barrel warm-up

...I routinely started every relay with half a dozen shots onto a sighter target
I was taught, before beginning a match, to shoot 10 rounds downrange into the backstop and not into the target. This serves to eliminate a cold bore flyer from a clean barrel, to warm-up the barrel, and to settle the shooter. I definitely use the same ammo that I am using in the match. After switching targets and positions, I shoot a few shots into the sighter bull again, mostly to check NPA, but also to rewarm the barrel. I shoot prone and position matches.
 
#13 ·
Dont overthink this, dance with who ya brung and when you feel like you and the gun have settled down shoot for score ;).
 
#17 ·
You should achieve acceptable accuracy from a cold barrel.

Having said that, over 50+ years of competitive shooting, I have never known any shooter who shoots to "warm" his/her barrel, but they shoot to foul the barrel, because 90-odd% of barrels shoot better when there is some fouling.

If it is below 45~50 degrees, you would be shooting "warming" shots all day long~ possibly dozens or more.
 
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