Powder Coat & Hot Barrels

[ChristopherO]

With such little experience concerning PC I found something out today. Running them in a hot barrel caused the boolits to fly way off bullseye. Allowing the barrel to cool down chucked them right back where they belonged on the paper. Is this the normal experience with powder coat and not giving time for the barrel to cool?

[Wheelguns 1961]

I have never had that experience. Were you shooting them from a machine gun?

[ryanmattes]

I use HiTek and heat doesn't affect it at all. In fact, when I throw coated bullets back in the pot, the lead melts out and the coating holds it's shape. I have to squish them to get all the lead out.

Might also be either the brand of powder or you might've gotten a bad cure.

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[Red River Rick]

It may not be the PC bullets, but rather a bedding problem.
There may be a point where the barrel is touching inside the forend, and moves the point of impact as the barrel warms up.

[oley55]

With such little experience concerning PC I found something out today. Running them in a hot barrel caused the boolits to fly way off bullseye. Allowing the barrel to cool down chucked them right back where they belonged on the paper. Is this the normal experience with powder coat and not giving time for the barrel to cool?

Never heard of it before. Does your "way off bullseye" mean shotgun patterning or a grouping shift? Perhaps a wee bit of information about weapon, caliber and etc, would help.

A better question would be, how could PC possibly cause this?

[ChristopherO]

The Specs:
35 Whelen, NOE 182 WFN GC's installed before powder coating (purchased from one of the venders on this board), 25 & 26 grains of H2400 with just a tuff of dacron fill over CCI 200LRP running at about 2,000 fps. Looking to duplicate a 350 Legend loading to see how I like it, should I decide to acquire one in the future for hunting in these straight walled states of the Midwest.

Shooting at 100 yards, the group was looking pretty good and I got carried away and kept banging them out without the usual cool down between shots as I was dialing the scope to print on the bullseye. Faulty thinking was that with half the powder that is loaded than for the 250 grain jacketed bullets (yes, I realize, completely different type of powder) that it was fine. I was in a time crunch, needing to meet a client soon and didn't allow wisdom to prevail, put the rifle away and resume when I could methodically sight these boolits in. Before the shots started opening up they were printing at edge of 4 o'clock to the bullseye in a promising cluster. Next thing my son, who is calling the shots through the spotting scope, says "Off the paper to the left." "Bottom of the target." "Back in the group." "Off the paper to the right." Yes, shotgun pattern, as mentioned above, from 4 to 6 " out of the pattern.

Then I touched the barrel and was surprised at myself to have allowed it to become so hot. I had three mouse fart loads with 7 grains of Bullseye powder and as an experiment they hit exactly where they always do. I set the rifle down to assist my son for about 15 minutes. During this time the barrel had cooled so I shot another of the H2400 loads at the target and it printed in the nice cluster already at 4 o'clock. Before packing up to leave one more boolit was sent toward a water jug at 100 yards and popped it with aplomb.

This had been a project rifle of an aspiring gunsmith 30 years ago who free floated the barrel, I just ran a dollar bill down the barrel to within 4" of the large ring (old Mauser that was sporterized). It had also been bedded by that fellow. I installed a Timney Trigger years ago. It is a shooter. I have never had problems with shots walking with this rifle, except for last year when the scope loosened. It is still solid after addressing that issue in 2020, as I checked to be sure. The only think I could attribute to this issue is that the PC, and possibly the softness of the range scrap the boolits were cast from, gave way down the hot barrel.
The Hammer Test on one of these PC'd boolits showed no loss of bonding of the paint to the lead upon being smashed previously.

The bore cleaned up very well last night with no signs of leading showing on the patches and the lands/grooves appear bright and defined as always. Thus, the reason for my post about this experience. I'm not here to malign powder coating, but to share what I saw on paper yesterday afternoon. The next trip to the range I'll meter the shots to a minute a piece, as is my normal custom on load development, to see if the results are much more satisfying.

[Castaway]

Confirm by doing same thing with jacketed bullets. Dollars to donuts is your barrel “walked” as it heated up.

[popper]

Dollars to donuts is your barrel “walked” as it heated up.
Yup. Done multiple mag dumps AR10 PC cast, no problems, 2400 fps carbine loads, 168gr GC..

[charlie b]

I agree.

I can shoot my .308 until the barrel is warm to the touch and it prints ~MOA groups with PC bullets and sub MOA with jacketed.

But, if it gets too hot the groups open up. This barrel only opens up to ~3MOA but it is noticable.

Warm to hot is not very defined yet. I need to get an IR thermometer to measure barrel temp cause this one is very sensitive. Cold is good. A bit warm is better. Hot is bad. Funny thing is POI doesn't really change, just the group size.

PC fouling and temp. I have run an experiment on cleaning with PC bullets. 150 rounds in 50 round sessions. The sessions were run with the first 30 rounds at sedate pace, keeping barrel warm. Last 20 ran the barrel up to too hot.

The second session of 50 rounds showed the best accuracy. Even the last 20 in a hot barrel were decent groups. The last 50 showed the buildup of fouling. After about 20 rounds it started opening up to 3MOA.

Cleaning after 150 rounds was about the same as after 20 rounds.

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[bangerjim]

Never heard of any problems with PC and hot barrels. I think your problem is as stated above with “walking”. Do not blame PC. Test with jacked as suggested.

[GregLaROCHE]

See what happens with a harder alloy.

[Geezer in NH]

Need to check the action screws for movement when tightened also. Is the action fully bedded? Something appears to be moving as it heats up.

[ourway77]

Does it cause minor melting or soften the coating

[Finster101]

It's not the powder coat.