Cartridge Gauge - Before/After Bullet Seating (6.5 Creedmoor)

[Rathmatik]

I just tried out my new RCBS Matchmaster Seater die for 6.5 Creedmoor with Hornady brass and Sierra 130gr TGK bullets. I really like the features of this die, and the micrometer appears to be spot on.

Now, I'm seeing something that I'm unsure whether it should be concerning or not. My cases are fitting into my Hornady Cartridge Gauge just fine after resizing. I have had a few out of 20 rounds that I just made that no longer fit the gauge after seating the bullet with this new die. I tried giving them a little nudge in the gauge, which then scraped the case near the bottom of the shoulder.

First off, what would be causing this happen? Second, is this concerning? All of the rounds were easy to chamber in my Bergara B-14 HMR.

This would almost seem like the cases are growing in length after seating, or is it an issue with runout? I don't have a runout measuring tool, unfortunately.

 

[mdi]

How do they chamber in your rifle?

I haven't had any luck with cartridge gauges, and I figger there are more things that could happen to a cartridge besides headspace, case length or bullet seating depth. I got a Garand and thought I needed a cartridge gauge for my semi-auto rifle. I fired about 200-300 HXP rounds before I tried reloading, and 4-6 out of ten of my handloads wouldn't fit the gauge. I bought new and once fired brass and still had problems with my handloads fitting the gauge. I even bought new RCBS dies and F/L sized each cartridge twice. (I checked on the CMP reloading forum and one older member replied "do they chamber?". They did chambered quite well so I gave up the fight). After a few hundred rounds I discovered the exiting brass was hitting the Op Rod hump on it's way out, dinging the rim enough to stop gauging correctly, but not visually noticeable. My fix; put the gauge in a drawer, somewhere...

 

[Blue68f100]

Are you crimping? If so you may be bulging the brass at the shoulder. No need to crimp.

As long as it fits the chamber that's all that's really counts. Now if you have a chamber gauge made from the barrel drop off, with the same reamer that did your chamber then you can use it instead of the gun. But as you use the gun, the throats will get longer the gauge will not. So if your chasing the lands you will have to use the gun's chamber.

 

[Rathmatik]

How do they chamber in your rifle?

I haven't had any luck with cartridge gauges, and I figger there are more things that could happen to a cartridge besides headspace, case length or bullet seating depth. I got a Garand and thought I needed a cartridge gauge for my semi-auto rifle. I fired about 200-300 HXP rounds before I tried reloading, and 4-6 out of ten of my handloads wouldn't fit the gauge. I bought new and once fired brass and still had problems with my handloads fitting the gauge. I even bought new RCBS dies and F/L sized each cartridge twice. (I checked on the CMP reloading forum and one older member replied "do they chamber?". They did chambered quite well so I gave up the fight). After a few hundred rounds I discovered the exiting brass was hitting the Op Rod hump on it's way out, dinging the rim enough to stop gauging correctly, but not visually noticeable. My fix; put the gauge in a drawer, somewhere...

They chamber just fine in my rifle. That is interesting to know. Yeah I figured it could be a number of things, just find it odd I suppose.

 

[Rathmatik]

Are you crimping? If so you may be bulging the brass at the shoulder. No need to crimp.

As long as it fits the chamber that's all that's really counts. Now if you have a chamber gauge made from the barrel drop off, with the same reamer that did your chamber then you can use it instead of the gun. But as you use the gun, the throats will get longer the gauge will not. So if your chasing the lands you will have to use the gun's chamber.

Nope, I don't crimp bottleneck cartridges. Yep, it fits the chamber fine. I didn't notice a difference between the ones that fit the gauge and the ones that didn't.

That makes sense. I'm close to 70 thousandths off the lands due to the B-14 HMR being magazine-fed, and I prefer not to single-load. Working well so far.

 

[mdi]

They chamber just fine in my rifle. That is interesting to know. Yeah I figured it could be a number of things, just find it odd I suppose.

Shoot 'em...