Barrel Heat's effect on Group Size

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Paul-in-PA
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Barrel Heat's effect on Group Size

Post by Paul-in-PA » Sat May 30, 2015 7:26 am

I have shooting my Browning 1895 BPCR for four month now, only shot 100 rounds so far. Think I have a load that shoots accurately for my skill at this point. My early trips to the range were normally ten round relays, my last two were 20 rounds. I have noticed on the last two outings that my groups open up as I shoot the 11th to 20th round, it takes me about 30 to 40 minutes to shoot the 20 rounds.

So my questions are:
- Does barrel heat effect the group size? I assume so based on what I have read. But looking for more specific BPCR theory.
- Is a minute between shots, too little time? The barrel gets warm too the touch. How long do folks wait between shot?
- - No blow tube, and I have not been wiping between shots. Just blowing lightly into the breech. Have seen a lot of debate on Blow Tubes, some say yes use, some say it does not matter.

On a side note, how long do folks let their BP loaded ammo sit around? Sometimes I work up a load, and load 50 round and it may take me two months to shoot it all. Does it matter.

Thanks in Advance

Paul

martinibelgian
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Re: Barrel Heat's effect on Group Size

Post by martinibelgian » Sat May 30, 2015 11:24 am

Paul,

What you're seeing is IMO not the result of your barrel heating up, but rather of fouling accumulating and reducing accuracy. If your fouling management consists of just lightly blowing down the breech between hots, odds are that's the point to correct. Just aboiut every competitive shooter will have some form of fouling management, be it wiping or blowtubing, after every shot.
I would suggest you give it a try too - make a blowtube (some flexible tubing, a drill and a fired case will do) or wipe (if shooting GG 2 humid - not wet - patches between shots will be a good starting point). I'm pretty sure you will be able to at the vzery least maintain accurcay, and probably even improve...

gunlaker
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Re: Barrel Heat's effect on Group Size

Post by gunlaker » Sun May 31, 2015 5:21 pm

A minuete between shots isnt going to hurt anything. When shooting outside in the hot sun the barrel can get too hot to touch and these rifles still seem to shoot pretty well. I worry about leaving a round in the chamber too long in a really hot rifle though.

Sometimes later targets are not as good as earlier ones due the effects of recoil wearing you down a bit, or eye strain.

Chris.

gunlaker
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Re: Barrel Heat's effect on Group Size

Post by gunlaker » Sun May 31, 2015 5:26 pm

Paul, one more thing. With repect to old ammunition. I usually shoot with zero neck tension, i.e. the bullets are a slip fit in the case so you can pull them out with yoyr fingers. I've found that sometimes very old ( 6 months or so maybe ) requires a lot more effort to pull the bullet out. Not necessarily a good thing I would expect.

Generally none of my ammunition sits around very long, usually less than a week or two. But I sometimes have leftovers in my safe. I still have a few rounds from a match a year ago and haven't brought that rifle out since then.

Chris.

Kurt
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Re: Barrel Heat's effect on Group Size

Post by Kurt » Sun May 31, 2015 7:52 pm

Chris.

I don't think you can get a black powder rifle hot enough to cook off a round in it. I have had my barrels get so hot the screw holding the forearm on burned my hand. I had rounds cook off shooting the M-60 where I had to break the belt to stop it, but never in a rifle.

Kurt

gunlaker
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Re: Barrel Heat's effect on Group Size

Post by gunlaker » Sun May 31, 2015 10:42 pm

Kurt I was just thinking of the effect on the lube. I imagine that the lube would melt if it sat in there too long. Im sure it cant be a good thing. I have never checked ( because my loads are mostly slip fit and an ejected live round leaves the bullet in the rifling so I can't check without driving the bullet out with a cleaning rod ).

Chris.

Kurt
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Re: Barrel Heat's effect on Group Size

Post by Kurt » Mon Jun 01, 2015 1:08 pm

Chris.

I have put rounds in the truck so the sun hits the box with the windows rolled up to see what effect the soft lube has in the case with different wads used all day long. The fiber and blue rubber cellulose wads where soaked with the oils clear through but the powder did not show signs of darkening from contamination. I don't worry about it anymore. They don't get that old from not getting shot.
Just this winter I had old .40-70 shells from 06 that have been sitting so long they turned gray. I pulled the bullet to recycle them and those wads where soaked through but the powder still looked like it was just loaded.
Besides the soft lube does more good in the bore when you shoot it.

Kurt

Lumpy Grits
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Re: Barrel Heat's effect on Group Size

Post by Lumpy Grits » Wed Jun 10, 2015 9:20 am

I think your deal'n with fouling taking control and mirage from either bbl heat or air temps or both.
LG
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Maj. Forrest Smith
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Re: Barrel Heat's effect on Group Size

Post by Maj. Forrest Smith » Wed Aug 19, 2015 10:54 am

From what has been said here, I think what you can start with is to blow tube or wipe between shots. If you decide to blow tube, use about 5 breaths through your lungs to start. If you decide to wipe, one wet match, one dry patch and then a dry chamber mop to start. You can vary these methods if you find they help solve your problem. Like with loading your rounds, be consist in how you do your fouling control to get a good read if you find this to help. It is a great learning curve you work on forever, lol.
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montana_charlie
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Re: Barrel Heat's effect on Group Size

Post by montana_charlie » Wed Aug 19, 2015 11:38 am

Paul-in-PA wroteCOLONI have shooting my Browning 1895 BPCR for four month now, only shot 100 rounds so far.

So my questions are:

- - No blow tube, and I have not been wiping between shots. Just blowing lightly into the breech. Have seen a lot of debate on Blow Tubes, some say yes use, some say it does not matter.
I think you have misinterpreted what you have read about blowtubes.
You sometimes hear about a load that can fire five or ten decent shots without (much) need for fouling control.
But, almost everyone else realizes that fouling control is an integral part of the game if 'accuracy' is your goal.

That control can be blowtubing to keep the fouling soft and moist, or it can be wiping the bore between shots to remove the fouling.

With your lever action rifle, blowtubing is probably your most reasonable option ...

CM
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Brent
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Re: Barrel Heat's effect on Group Size

Post by Brent » Wed Aug 19, 2015 12:01 pm

Just a few more comments to add to the list.

1. You EXPECT the group to get larger as you fire more shots. That is as simple fact of a larger sample size. Just as a 10-shot group is, on average, larger than a 5-shot group, and a 5-shot group is larger, on average, larger than a 3-shot group, so too is a 20-shot group larger than a 10-shot group. How much larger depends on a host of things.

2. If your barrel has internal stresses for any reason, or if the fit of barrel shoulder to breach face is not perfectly even around the circumference of the barrel/breech threading due to, for instance, the breech face not being perfectly squared to the threaded hole that the barrel will mount in, then the barrel will "walk" as it heats up and the group will get larger (generally moving in one direction - predictably).

3. Your eyes will tire and your ability to aim will become a bit less precise.

4. The environment is temporally autocorrelated - which is to say that conditions are changing and there will be more change, on average, between first and last shots when you are shooting 20 rounds relative to when you were shooting 10.

Any or all of these can happen - plus the fouling issue. So, there are LOTS of reasons why this might happen.
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DRCook
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Re: Barrel Heat's effect on Group Size

Post by DRCook » Wed Aug 19, 2015 2:27 pm

On a side note, how long do folks let their BP loaded ammo sit around? Sometimes I work up a load, and load 50 round and it may take me two months to shoot it all. Does it matter.
I just shot some that I loaded back in 2009. They shot the same as the ones that I loaded 4 weeks ago. They were stored in a box in the basement, not too hot, not too cold.
drcook = david r, not dr. but thanks for the compliment :)

Maj. Forrest Smith
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Re: Barrel Heat's effect on Group Size

Post by Maj. Forrest Smith » Thu Aug 20, 2015 3:17 pm

Dave is right on old bullets. Though where they are stored and what type of lube that was used might have a lot to do with it. I do not know the shelf life of paper patch bullets. Maybe Brent or Kenny can weigh in here on how long they have let their paper patch bullets go with out any effect on the paper, thus effect their accuracy.

We had one guy that shot some rounds he had loaded for Raton 4 years ago and ended up winning the monthly match in OKC! And yet, we have another gentleman that if he has not shot his lead bullets in 6 months, he pulls them and cast them again.

Joe Scott said it best to me once. "We take about 75 steps in making a round to shoot, about 65 of them are voodoo!" Other words, there are steps each of us take that the next shooter might not feel is necessary, but if it may you "feel better" to do those steps and you have taken them to the range and put them on the target well, go ahead and do it, until you decide it isn't needed or you need to add another step to your process. If it makes you feel more confident when you go to the shooting line, do it. There is just to many successful shooters out there that do it differently, but still hit the target. I have decided there is no one way to get there. Brent and Kenny have found their way to make paper patch bullets work well. Others like to slip fit their bullets, some neck size only and there are those that full length size. All of these ways are can be right or wrong, depending if you have found the right combination for your rifle.

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