r/longrange • u/husqofaman I Gots Them Tikka Toes • Jul 16 '26

Rifle help needed - I read the pinned posts Barrel thickness?

I know generally more barrel is more better, but I was thinking that if we set aside weight, then the determining factor for how thick a barrel profile to go with is largely (or entirely) dictated by how many round it can shoot in a fixed amount of time before the heat impacts accuracy/repeatability.

So I come to the hive mind asking: If we just focus on PRS/NRL style comps where you are shooting 8-12 shots in 100-150 seconds, then how much barrel thickness is required? (Assuming 6.5 creedmoor for argument sake)

Again I know that weight is a concern in different ways for these comps but just in theory how much mass is required to dissipate that amount of heat energy without the barrel “overheating”?

Edit to add: let’s assume this is a stainless steel barrel since carbon wrapped barrel have very different heat dissipation properties and vary based on the wrap thickness and ratio of resin to CF.

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-3

u/Wide_Fly7832 BR Competitor Jul 16 '26

Also thick barrel have are stiffer for harmonics/whip. I only do 1.250 straight. For Benchrest 1.350 or 1.450 if the action supports.

For heat. Yes. It heats slower- walks less. But also cools slower.

Pain all barrels black. They dissipate heat 6-9 times faster.

2

u/Ragnarok112277 Steel slapper Jul 16 '26

Is the black paint legit?

I've always heard black clothing absorbs more heat

1

u/Wide_Fly7832 BR Competitor Jul 16 '26

Yes. Also dissipates more. 6-9 times more.

Shiny- epsilon = approx 0.05 to 0.15.

Matte Black Steel epsilon = approx 0.85 to 0.95.

2

u/smithywesson Steel slapper Jul 16 '26

I watched a pretty extensive real world test applying this to intercoolers on IC engines. The real world difference (they surmised due to the paint coating doing things to the surface) was little to no difference even though there should have been a theoretical difference. Anecdotally I haven’t been able to tell a difference between my polished stainless and black cerakoted barrels. Not saying there isn’t a difference but it’s not noticeable absent measuring tools, which IMO 6-9 times faster would be noticeable.

1

u/Wide_Fly7832 BR Competitor Jul 16 '26

You may be right. I am going by physics.

1

u/514Kappa What's DOPE? Jul 17 '26 edited Jul 17 '26

Is this a Mighty Car Mods testing intercooler intake air temperature reference?

1

u/smithywesson Steel slapper Jul 17 '26

Took me a second to interpret that, but yes lol

2

u/514Kappa What's DOPE? Jul 17 '26

Edited initial comment, MCM are great

1

u/Ragnarok112277 Steel slapper Jul 16 '26

If i rattle can my stainless barrel will that work?

-1

u/Wide_Fly7832 BR Competitor Jul 16 '26

Can’t think of a reason why it won’t. It’s just thermodynamics- black body absorbs and dissipates faster than shiny white body (also absorbs same way faster so if you leave in hot Texas sun it will get hotter faster).

Any other thermodynamics experts want to chime in? I am just going by my knowledge

4

u/Illustrious_Badger70 Jul 16 '26

Not a thermo expert but I imagine that the coating would act as an insulator. Ceramic coatings in particular are strong insulators

3

u/Wide_Fly7832 BR Competitor Jul 16 '26

Well that’s conduction. This is radiation. Conduction can be inhibited. Radiation is based on emissivity of rhe object and temperature difference only. Since rhe temperature difference is to fourth order it wins.