Winchester 92 44-40 headspace question

[Clarkm]

Someone is calling me who is rebarrelling his 44-40 and seems to think the rifle headspaces on the case mouth, not the rim.

Is this possible?

[kcstott]

Ask him to look at the head space gauge.
they head space off the rim

[pacrat]

Someone is calling me who is rebarrelling his 44-40 and seems to think the rifle headspaces on the case mouth, not the rim.

Is this possible?

NO!

See post #2

[Clarkm]

I have no win 92 in 44-40, but I have one in 38-40 that I could check and then send him an email.

The brass case head rim is 0.054" thick.
The masking tape is 0.005" thick.
3 layers of masking tape fits = 0.015" spacer
4 layers of masking tape is tight = 0.020" spacer.

The headspace is therefor between 0.069" and 0.074"

The SAAMI drawing shows the brass rim between 0.055" and 0.065"
The new Starline brass is therefore out of spec.

The SAAMI drawing shows the chamber headspace between 0.065" and 0.072"
The rifle may or may not be in spec.

[ar15barrels]

Someone is calling me who is rebarrelling his 44-40 and seems to think the rifle headspaces on the case mouth, not the rim.

Is this possible?

Rimless cases headspace off of the mouth.
44-40 has both a rim and a shoulder.
It's gonna headspace off the rim if the shoulder is sized properly.

[ar15barrels]

I have no win 92 in 44-40, but I have one in 38-40 that I could check and then send him an email.

The brass case head rim is 0.054" thick.
The masking tape is 0.005" thick.
3 layers of masking tape fits = 0.015" spacer
4 layers of masking tape is tight = 0.020" spacer.

The headspace is therefor between 0.069" and 0.074"

The SAAMI drawing shows the brass rim between 0.055" and 0.065"
The new Starline brass is therefore out of spec.

The SAAMI drawing shows the chamber headspace between 0.065" and 0.072"
The rifle may or may not be in spec.

Tape is compressible under the measuring forces of closing the action.
Use real gauges made of non-compressible materials.

If you absolutely must do it the hoaky way, use a brass case that you have previously measured and make metal shims from shim stock that you have confirmed the thickness of.
At least that way, you are using a non-compressible gauging method.

[Scota4570]

Making headspace gauges for rimmed cartridges is easy. Since one already has a lathe to do barrel and chamber work, why not just make them?