Non SS gas blocks on SS Barrels

[Ovaj]

Hey guys, my BCM SS410 (non ionbonded) 18" arrived today and i realized that the gas block im gonna use on it is not SS (YHM Low pro)

Am i gonna run into trouble running a non SS gas block on the SS barrel?

I ask because i've been hearing that if the expancion rates differ too much during rapid fire, the block could get off alignment, rendering the gun useless until resolved.

Is this something i should be concerned? Im still on time to get a SS block.

Thanks a lot guys!!

[MistWolf]

No. The outside diameter of the barrel will increase, the internal diameter of the gas block will decrease. They will fit tighter to each other when hot

[bp7178]

No. The outside diameter of the barrel will increase, the internal diameter of the gas block will decrease. They will fit tighter to each other when hot

Is this unique to the YHM block?

When I had to get my Novske block, 17-4 Stainless, off of the 416R stainless Noveske barrel, I heated both in the over.

As a matter of fact, to make the gas block easier to put on, I heated it up in the over and it slid on like butter.

[Ovaj]

I do understand the mechanics behind the barrel heating up and expanding.

Now the concept of the gas block reducing it's Internal Diameter under high temps eludes me.

Would like some more input on this matter, im building in about a week.

Thanks guys!!

[MistWolf]

Sorry guys, I had a brain fart about the ID. Blame it on all the forms I've had to fill out the last couple weeks turning my mind into mush. ID does indeed increase when hot

[Eric D.]

Coefficient of thermal expansion for 410 SS: 5.5 x10^-6 in/in-deg.F

For all carbon steels, the coefficient is approximately 7.3 x10^-6 in/in-deg.F

Assuming equal temperatures for both the barrel and the gas block, the block will expand at a greater rate. Considering heat has to be transferred from the barrel to the block, however, the barrel will begin expanding first. Even if the barrel and block got to 1000 degrees F, the difference in expansion will only be a few ten-thousandths of an inch. I don't think you will have a problem.

[Ovaj]

Coefficient of thermal expansion for 410 SS: 5.5 x10^-6 in/in-deg.F

For all carbon steels, the coefficient is approximately 7.3 x10^-6 in/in-deg.F

Assuming equal temperatures for both the barrel and the gas block, the block will expand at a greater rate. Considering heat has to be transferred from the barrel to the block, however, the barrel will begin expanding first. Even if the barrel and block got to 1000 degrees F, the difference in expansion will only be a few ten-thousandths of an inch. I don't think you will have a problem.

Sold!! I'll report back as soon as i run the gun hard.

Thanks to all the members who took their time for me and specially to Eric D for this concise post.

Thanks guys!!