Checking OAL with full sized or neck sized brass?

[Nessal]

I recently checked my OAL in my Remington 700 and I got different figures using brass that are full sized and brass that are firm formed with only neck sizing. I have the Stoney Point OAL gauge with the modified case. I assume that this modified case is a full sized case. When I do the measurement, I confirmed that it gave me shorter OAL measurement compared to a neck sized measurement. I checked the neck sized OAL by putting a bullet into the brass and them chambering it to get the measurement.

Would it not be safe to say that the neck sized OAL is more reliable especially since it is fire formed to my chamber? Or are you suppose to always used full sized cases to check OAL?

 

[Fuzzball]

Re: Checking OAL with full sized or neck sized brass?

The distance from the bolt face to the lands is the same no matter how you size the cases. Ditto the length of the magazine box. ??

 

[Victor N TN]

Re: Checking OAL with full sized or neck sized brass?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">The distance from the bolt face to the lands is the same no matter how you size the cases. Ditto the length of the magazine box. ?? </div></div>

+1...

 

[Nessal]

Re: Checking OAL with full sized or neck sized brass?

Ehhh, I'll remeasure everything and try again.

 

[ChrisGarrett]

Re: Checking OAL with full sized or neck sized brass?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nessal</div><div class="ubbcode-body">I recently checked my OAL in my Remington 700 and I got different figures using brass that are full sized and brass that are firm formed with only neck sizing. I have the Stoney Point OAL gauge with the modified case. I assume that this modified case is a full sized case. When I do the measurement, I confirmed that it gave me shorter OAL measurement compared to a neck sized measurement. I checked the neck sized OAL by putting a bullet into the brass and them chambering it to get the measurement.

Would it not be safe to say that the neck sized OAL is more reliable especially since it is fire formed to my chamber? Or are you suppose to always used full sized cases to check OAL? </div></div>

Ideally, all of our modified cases are made from 1x cases and are fired from the particular chamber that we're trying to measure. Unfortunately, this isn't practical, nor cost effective.

I've dropped fired cases from my chamber into case gages and I've done so with my modified cases. In some instances, the shoulder on a modified case is bumped back pretty far and this will affect your OAL measurement. They're not fireformed to any chamber.

If you only neck size, that case will fit more tightly to that particular chamber it's been fired in, hence it'll be slightly longer than a FL 'improperly' sized case, as one might find with the Hornady LnL cases.

Remember, you measure from the head to the tip, to get that ogive/lands measurement, so case sizing/headspace will matter a few thousandths' worth.

Chris

 

[ChrisGarrett]

Re: Checking OAL with full sized or neck sized brass?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">The distance from the bolt face to the lands is the same no matter how you size the cases. Ditto the length of the magazine box. ?? </div></div>

+1... </div></div>

When you use a modified case, you're not measuring from the bolt face, but the back of that modified case. The headspace of that particular modified case, will matter in the overall measurement.

I think this is what the OP is asking about, a modified case with too much shoulder bump vs. a neck sized case.

Chris

 

[Enios]

Re: Checking OAL with full sized or neck sized brass?

That's why I like to use a fire formed case properly sized (.001 shoulder bump) with the split neck. Chamber it at least 5 times or until you get the same measurement several times. I drill out the primer pocket and have and old screw driver cut off at the shaft where I can push the bullet back out.