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View Full Version : Mark I/II/93R: Is "cold barrel" a thing?



Bar Nuthin
09-14-2020, 09:53 PM
Decided to sight my Mark II G @ 50 yards today. Made adjustments shooting 10 shots at center. Walked down to look over the target, then went back and loaded 5 rounds and shot at top right. Walked down and looked at target, then repeat - 5 rounds at bottom left target. Repeat, Repeat. The time between each 5 shot group was probably 5 to 10 minutes.

Each time, the first of five rounds went low and the next four were spot on. I showed the target to my neighbor (who's more experienced) and he simply stated "cold barrel".

Is that a reasonable explanation, or is it just coincidence that i got a flyer on each of my first shots? CCI Standard Velocity, 5-8 mph breeze at my back, 70°F, sunny. Shooting from a bench with a bipod.

https://static.wixstatic.com/media/2fc387_38785f4c539c42249b3a1a0bd24084a0~mv2.jpg

Fasteddie01
09-16-2020, 08:53 AM
I've read a lot about that 'cold bore' thing and it seems the popular opinions run towards a 'carbon ring' at the mouth of the chamber. google that phrase on the net and you'll find lots of info. You can't see the 'ring' just looking into the chamber - you need a bore scope to see that and the overall condition of your barrel. Amazon has them for around $50 or so - search amazon for 'Teslong'
bore scope' and be sure to get the one that has 0.20 " scope. There are some that are larger diameter and will not fit a .22. For cleaning the carbon ring I recommend Bore Tech C4 Carbon Cleaner. It's a bit pricey but you only need a few drops on a patch, only insert into the chamber until meets the rifling and let it sit there about a half hour. Then clean as normal. If your borescope shows the barrel having carbon all the way thru, you can use C4 there too. I had a .223 with really black rifling most of the barrel, and it cleaned up totally! Of course, I had to deal with the copper fouling with another 'special' cleaner for that.

rmeyerwy
09-16-2020, 09:35 AM
I sure am not an expert by any means, and most of my shooting for groups has been centerfire, but I cant remember ever having a 1st shot that was that far off and then things settled back in, just seems like there is something else at work here to me. I have had a fair amount of 1st shots hit right where I want, then things start to spread out.

I dont know, I would check action screws, barrel free floating, something just seems odd to me..

Interesting..

Fasteddie01
09-16-2020, 10:19 AM
From what I've read the carbon ring builds up after several hundred shots, especially if using dirty ammo (Aguila, T-bolt, etc). The theory about cold shot is that the ring 'solidifies' sorta like cooked sugar in peanut brittle. Then the first shot is displaced by the cold 'sugar', after which it is heated and softened so doesn't mess up the next shots. If allowed too cool a few minutes, the process repeats.
Now, that's just what I've read about how it goes. I just got a Teslong this spring and found black carbon ring on my Savage 64 with prob 2-3000 rounds. As I said, the C4 took care of it easily. My 64 is only a 1" gun with most ammo, tho the SK-Standard Plus has done close to 0.5" ($10/bx) which I don't use much. Fed Auto-match is the standard fare for that one. The carbon may account for the frequent fliers, but that may be the low-cost ammo? I haven't used much of the 'high=priced spread' in the 64.

EDIT - I searched and found one person on RFC saying he had good results with Acetone on the carbon. *Fingernail polish remover has acetone and can be had at a Dollar store. http s://www.rimfirecentral.com/forums/showthread.php?t=1161431

Fasteddie01
09-16-2020, 12:43 PM
Here's the thread that 'defines' that problem - this is the last I'll post ;-)
Ed
https://www.rimfirecentral.com/forums/showpost.php?p=11766079&postcount=1

rmeyerwy
09-16-2020, 12:51 PM
Fasteddie01, interesting read!

Learn something new every day. Sure was simpler 30 years ago, you just loaded up and went and shot...

Thanks for the info..

Fasteddie01
09-16-2020, 10:16 PM
rmyer - I'm retired so if something interests me I dig into it. I just got a B22 and want to go after the elusive 0.5" groups with a low-priced rifle. All I keep seeing are people with $1000 guns and $1000 scopes, and I feel left out. I've bought 13 diff ammo and only tested 4 so far - only out twice and it's advised to test like 50 rounds or so for each brand. Fortunately, I'm only buying under $10/bx50 (CDN) so it won't get too expensive. I'll save those for later, right now I'm doing $4-6 range. CCI-MMs are $10-12/100 so that'll be my top price for a while. I did buy a couple boxes of SK Standard Plus for $12 tx-inc (15% here in Can) but that was before I bought the B22. I've got a Marlin-60 that likes it, too.

Bar Nuthin
09-21-2020, 08:47 AM
Thank you! Great find! I think I'll go ahead and perform the cleaning process even though I don't currently have a bore scope. We have some nice weather days forecasted this week so I can hopefully get out to shoot some paper.


Here's the thread that 'defines' that problem - this is the last I'll post ;-)
Ed
https://www.rimfirecentral.com/forums/showpost.php?p=11766079&postcount=1