6.5 SS Sherman Short Headspace Concerns

[J_D_ELR]

I bought a used 6.5SS barreled action from here and finally got all the reloading pieces I needed to get this started.

I have loaded 6CR, 6 Dasher, 22GT, and 224 Valkyrie, but had no 6.5mm bullets, mandrels, bushings, or magnum case blocks, etc, those finally arrived......and the long weekend was upon us.

The barreled action came with unfired, unsized brass, and a lots of fired brass. I'm going with the Berger 153.5's for an ELR gun. Shoulder to Base was 1.529 on the 1x fired, and I sized and bumped to 1.524

I removed the firing pin and ejector from the bolt, and proceeded to measure for BTO Jam which was 2.198, I started off with roughly a .050 jump and my starting BTO is 2.150 which is .048 but close enough. No issues with the bolt closing, so I proceeded to load up 10 rds at 54gr of N560 and another 10 rds at 55gr to start off slowly and get a decent baseline. I was told 57gr would be a better starting off point.

I bought a go gauge from Rich and it arrived today...I measured it at 1.515......new brass was 1.514 which from my measurements above is concerning me on the amount of headspace this rifle has. I put a piece of tape over the go and measured it correctly at an additional 2 thou at 1.517, but I can close my bolt easily still with the sized and bumped brass which is .012 of headspace. Is that excessive for these? I'm much closer on my 6 Dasher and 22GT PRS setups.

 

[elkaholic]

I bought a used 6.5SS barreled action from here and finally got all the reloading pieces I needed to get this started.

I have loaded 6CR, 6 Dasher, 22GT, and 224 Valkyrie, but had no 6.5mm bullets, mandrels, bushings, or magnum case blocks, etc, those finally arrived......and the long weekend was upon us.

The barreled action came with unfired, unsized brass, and a lots of fired brass. I'm going with the Berger 153.5's for an ELR gun. Shoulder to Base was 1.529 on the 1x fired, and I sized and bumped to 1.524

I removed the firing pin and ejector from the bolt, and proceeded to measure for BTO Jam which was 2.198, I started off with roughly a .050 jump and my starting BTO is 2.150 which is .048 but close enough. No issues with the bolt closing, so I proceeded to load up 10 rds at 54gr of N560 and another 10 rds at 55gr to start off slowly and get a decent baseline. I was told 57gr would be a better starting off point.

I bought a go gauge from Rich and it arrived today...I measured it at 1.515......new brass was 1.514 which from my measurements above is concerning me on the amount of headspace this rifle has. I put a piece of tape over the go and measured it correctly at an additional 2 thou at 1.517, but I can close my bolt easily still with the sized and bumped brass which is .012 of headspace. Is that excessive for these? I'm much closer on my 6 Dasher and 22GT PRS setups.

.012" is FAR too much headspace and you'll likely be separating the case head!! Id be calling your smith.

 

[J_D_ELR]

.012" is FAR too much headspace and you'll likely be separating the case head!! Id be calling your smith.

Bought it this way from here. No smith to call.
All my other rifles are Impact Precision 737r actions. This is a Remington 700 that was chambered by Straight Jacket Armory.

They are cutting a B spec barrel now for my Impact.

 

[lancetkenyon]

I have/had 4 different 6.5SSs. All the original chamber.
The first two used the old 30° brass you had to fire form.
The second two use the 40° brass. Virgin brass was .002" from fired brass. Not .012". That is a lot.

Who built the rifle originally? I would think, even though you bought it used, the smith should make it right.

 

[J_D_ELR]

Any chance these old Remingtons just have a sloppy bolt? Do my numbers seem way off on the go gauge and case measurements? Would erosion of the chamber account for .010 using high pressure loads?

 

[elkaholic]

Any chance these old Remingtons just have a sloppy bolt? Do my numbers seem way off on the go gauge and case measurements? Would erosion of the chamber account for .010 using high pressure loads?

No and no

 

[J_D_ELR]

I just measured this again this morning. checked a few fired unsized cases for baseline of the chamber.

In the comparator, set that to zero, and the new virgin brass was -.0120 shorter from the shoulder and same -.0120 for the go gauge.

The assumption is the case is stretching 12 thou, but I'm going to pull the bolt again later, without the ejector and firing pin and put a tape over the end of the go gauge to see if it really is headspace.

Fired brass......



Virgin Brass......



Go Gauge.....



sized and bumped brass at 3 thou.



is 12 thou normal stretching for these cases?