6.5 Creedmoor

[Gary]

Shot my 6.5 Creedmoor RPR yesterday to gather more "empirical" data, primarily Headspace data. I purchased some new from Hornady brass last year and got a case head separation on the second firing. When I checked the headspace (from the middle of the shoulder to the base of the case I was getting 1.495 on most and NONE of them up to the usual 1.5" range. So I fired a couple of factory Hornady rounds and measured the fired cases and both were exactly 1.550". Can I use the Hornady brass or should I scrap them?

 

[Ben]

I don't have an answer for you, but based on what you just said, it doesn't sound very promising.

Ben

 

[Spindrift]

Wow, that’s a lot of excess headspace! Was this after resizing?

The safest thing, would be to get new cases. A couple of ideas to try and salvage cases with excess headspace. I’ve never tried them, since I use mostly cartridges with plentiful range pickups

1) expand necks to overbore diameter (.30-cal, for instance). Resize in creedmoor die that is properly adjusted. This will make a false shoulder at the base of the neck, to headspace on. Flow of brass under obturation/pressure will be distributed more evenly

2) Load cartridges to full land contact, and crimp. The case should then headspace on the ogive; again, leading to more distributed flow of brass

3) Both the above

 

[Gary]

Out of the package and loaded, rookie mistake.

 

[Gary]

Wow, that’s a lot of excess headspace! Was this after resizing?

The safest thing, would be to get new cases. A couple of ideas to try and salvage cases with excess headspace. I’ve never tried them, since I use mostly cartridges with plentiful range pickups

1) expand necks to overbore diameter (.30-cal, for instance). Resize in creedmoor die that is properly adjusted. This will make a false shoulder at the base of the neck, to headspace on. Flow of brass under obturation/pressure will be distributed more evenly

2) Load cartridges to full land contact, and crimp. The case should then headspace on the ogive; again, leading to more distributed flow of brass

3) Both the above

I've already pulled all that I had loaded and your suggestions might just work but I'm a bit skid-ish doin' that, but a couple for testing purposes shouldn't hurt. Tongue in cheek on that last comment.

 

[fiver]

sounds like you just haven't fire formed your cases yet.
a lower powered round will do that to you and can even make the primers 'look' like you have high pressure.

what spin is saying to do, is to create a false shoulder to hold the cases back to the bolt and let the pressure push everything out to fit the chamber so your not flowing so much metal forward from the web area.
it's an old trick many of us use when we are forming Ackley type cases.

you can also simply seat the bullets out to jam the rifling, but you have to drop the load to compensate for the higher engraving pressure and higher initial pressure rise before the bullet even starts moving.

cast is going to be a little different pressure MAP because of the reduced loads, and that's why I like to use a full on jacketed load as my first firing with smaller sloppy fit factory new cases.

 

[Gary]

So, if I understand, I should load a full on jacketed load and let er rip! I can do that.

 

[fiver]

yep only way to get a true brass meets chamber fit I know of.
unless you got a die set that matches it real well, then you can hydro form the cases.

 

[RBHarter]

303 Britt tape ?

I'm on the neck up and short size school bus .

Seems odd that there would be so much room .

Is this a Savage by any chance ? I bought 223 Axis and had a bunch of mis/fail to fires and found too much head space the fix was simple and hid the roll stamps .

 

[Gary]

Ruger RPR that shoots factory just fine. As I said earlier the brass in question was purchased by me from Hornady as new brass. Factory ammo shoots just fine, I was just concerned with the "short" datum point (1.495) on the new brass. From now on I will headspace gauge ALL new brass.
The factory rounds I shot yesterday both measured 1.550 after firing. I think that's probably the max chamber size.

 

[Gary]

One other question; would annealing the brass that I pulled down help the brass ? That way it would be new brass, annealed then fired.

 

[fiver]

it should be annealed already.

 

[Gary]

Yep, I agree, but it shouldn't have been short either.