Can I use Hornady Headspace comparator on factory brass and resize my brass to those specs?

[BachmannBlackOut]

Most of my brass that I have is my once fired Aguila 300BLK from my chamber. It all ran just fine. So I was wondering if I can use my headspace comparator to measure my factory ammo and resize my brass to the same measurements.

[dellet]

Most of my brass that I have is my once fired Aguila 300BLK from my chamber. It all ran just fine. So I was wondering if I can use my headspace comparator to measure my factory ammo and resize my brass to the same measurements.

You can, but why would you go to all the trouble of learning to handload just to produce mediocre out os spec ammo?

See thread

viewtopic.php?f=141&t=108462

[popper]

Wrong way to set head space. Basically is a 'datum' point on the shoulder for bottleneck cases. Normal case gauge and feeler gauge will work. Proper way is to size , pushing shoulder back slightly till you get easy bolt closure. Or the tape method to measure. Or get go/no-go gauges and pull the ejector from the bolt. Comparator has caliper/attachment error/inconsistency built in. Little oil or dirt anywhere and your off a few thous.

[rlandry6]

Any case gauge is going to have the min/max headspace grooves machined into the base. Anywhere between the two surfaces should give you headspace that will work n about any gun. It won't let you get an exact measurement.
IMHO, you are better off with one of the micrometer headspace gauges. They run around $50 but worth the money. I have one for every caliber.

[dellet]

Wrong way to set head space. Basically is a 'datum' point on the shoulder for bottleneck cases. Normal case gauge and feeler gauge will work. Proper way is to size , pushing shoulder back slightly till you get easy bolt closure. Or the tape method to measure. Or get go/no-go gauges and pull the ejector from the bolt. Comparator has caliper/attachment error/inconsistency built in. Little oil or dirt anywhere and your off a few thous.

I’m not sure where to start with the poor information provided here, but it needs correcting.

The Op is not checking headspace, he is trying to duplicate ammo that he feels is working well. This is absolutely the correct use of the comparator tool. It may not be the best application for best performance to duplicate factory ammo, but it is the correct use.

Where exactly do you find brass that is too long to chamber?
In general you can’t buy basic brass that you can push the shoulder back until the bolt closes and even then you need to measure that and move it back your chosen amount. I think you’re confusing headspace with bullet jump/jam and a comparator is considered one of the correct tools for either process.

Adding tape to the base of a case, go/no go gauges have absolutely no function or relative information to the question asked. The Op has more information that is more accurate and relevant in his other thread that was linked, than either of those methods could ever provide.

Please name one measuring device that will not suffer from inconsistent readings when set up or used improperly.

Based on the questions asked, and information provided by BachmanBlackout, he’s well on his way to making safe, quality reloads.

[popper]

Gee whiz Dellet. Just get a fired 223, hacksaw the shoulder off, debur, lube and stick in die. Factory stuff may fireform to YOUR chamber, or not.Excessive HS just wears PP faster. Use the comaparator if you got it , I don't care.

[dellet]

Gee whiz Dellet. Just get a fired 223, hacksaw the shoulder off, debur, lube and stick in die. Factory stuff may fireform to YOUR chamber, or not.Excessive HS just wears PP faster. Use the comaparator if you got it , I don't care.

If all you were ever going to load is someone else’s used brass and wildcats, that might work. For 95% of people who load it won’t.

If PP is primer pockets, excessive headspace has nothing to do with wearing them.

[popper]

Uh, excessive HS will cause primer backout which is then slammed back into the PP and expanding it. After a few times, PP is loose. Can't help it if just using factory ammo but if reloading factory BO brass it does make a difference. BO chambers are all over the place. Ejector swipes, bent rims, etc I see from P.U. 223 stuff shows most chambers aren't 'correct'. Make good ammo or just OK? Just saying.

[dellet]

Uh, excessive HS will cause primer backout which is then slammed back into the PP and expanding it. After a few times, PP is loose. Can't help it if just using factory ammo but if reloading factory BO brass it does make a difference. BO chambers are all over the place. Ejector swipes, bent rims, etc I see from P.U. 223 stuff shows most chambers aren't 'correct'. Make good ammo or just OK? Just saying.

Everything you describe is more related to over gassing, over pressure, than too much headspace or an incorrect chamber. It's the same reason small base dies were invented, to remedy a problem that should not be happening in the first place.

A sign of too much headspace is thin brass in front of the web because it stretches there, in length.

A loose primer pocket is because the web expands in diameter due to much internal pressure, same reason base is driven into the ejector hole.

Swipes and bent rims are because the case is trying to be pulled out of the chamber while it's still expanded from firing. The bolt is opening too quickly because the gas system is not tuned properly.

None of this has anything to do with the chamber other than the load might be too hot for it.