Another Head Scratcher

[Coyotefurharvester]

If a case is a tight chamber fit at the shoulder/body transition you will get a false headspace fit measurement. Than if the actual headspace is large enough, the firing pin will drive the case forward with a loss of striking energy and less primer indentation. The false fit would also effect the "touch" feel and measurement of bullet seating. The factory modified case will certainly be less in diameter than a fired case that hasn't been body sized(at least mine are).

 

[284winner]

Well I feel like an incompetent fool. Found the problem. The modified case wasn't all the way in the chamber. It was the only thing I could think of trying. I tapped on the case while it was off the threaded tool with a piece of round stock flat to the case head with a brass hammer. The case actually seated quite a bit further till stopping against the shoulder. Kinda though that's where it was all along. Apparently the chamber is tighter than I thought. Wound up getting correct measurement numbers. The head scratching is over.

 

[Bill Norris]

Well I feel like an incompetent fool. Found the problem. The modified case wasn't all the way in the chamber. It was the only thing I could think of trying. I tapped on the case while it was off the threaded tool with a piece of round stock flat to the case head with a brass hammer. The case actually seated quite a bit further till stopping against the shoulder. Kinda though that's where it was all along. Apparently the chamber is tighter than I thought. Wound up getting correct measurement numbers. The head scratching is over.

You cannot feel the slight hang up of the web area of a case when pushing it in by hand. you are not incompetent. LOL.

 

[284winner]

You cannot feel the slight hang up of the web area of a case when pushing it in by hand. you are not incompetent. LOL.

Doing this stuff so long sure doesn't mean a thing. This lesson sure shows how the most elementary error can puzzle someone.

 

[Bill Norris]

Doing this stuff so long sure doesn't mean a thing. This lesson sure shows how the most elementary error can puzzle someone.

I like to push the case into the chamber a couple of times to make sure I hear it tapping the shoulder area of the chamber prior to actually checking the BTO.

 

[284winner]

I will say the chamber is tightee than any I've ever used a modified case in. After firing and cleaning the case 3 times before threading the primer hole, I'd have thought the case would fit perfectly. Having to tap it into the chamber to get it all the way in is real odd. I've had them snug but never like this.

 

[Bill Norris]

I will say the chamber is tightee than any I've ever used a modified case in. After firing and cleaning the case 3 times before threading the primer hole, I'd have thought the case would fit perfectly. Having to tap it into the chamber to get it all the way in is real odd. I've had them snug but never

I normally run my threaded case into my F/L bushing die (without the bushing) before use. That way it is exactly what my reloaded case will be like.

 

[284winner]

I normally run my threaded case into my F/L bushing die (without the bushing) before use. That way it is exactly what my reloaded case will be like.

I shot that case three times and resized it all three times. Weird situation.

 

[Bill Norris]

I shot that case three times and resized it all three times. Weird situation.

Absolutely strange. But sometimes the die will not size the case quite enough at the web. I had to take a few thousandths off of the face of my shell holder to get one of my dies to work properly.

 

[284winner]

Absolutely strange. But sometimes the die will not size the case quite enough at the web. I had to take a few thousandths off of the face of my shell holder to get one of my dies to work properly.

That's a thought. Keep that shell holder for just that cartridge. Never had the problem with any other 284 cases on other calibers. Something to think about

 

[Bill Norris]

That's a thought. Keep that shell holder for just that cartridge. Never had the problem with any other 284 cases on other calibers. Something to think about

Exactly what I did for my 260AI.

 

[284winner]

Exactly what I did for my 260AI.

I'll have to measure the area that's causing that tight fit. Seems like I measured that case against others at the base and it was the same. I'll recheck it

 

[divingin]

I normally run my threaded case into my F/L bushing die (without the bushing) before use. That way it is exactly what my reloaded case will be like.

Be careful doing this with small base cases (223, in my experience.) There isn't much thickness left after drilling and tapping the case, and the shellholder will rip the rim off. I've actually done it twice, because I made a case for a friend, and forgot I had destroyed mine by trying to post-size it earlier in the year.

 

[Bill Norris]

Be careful doing this with small base cases (223, in my experience.) There isn't much thickness left after drilling and tapping the case, and the shellholder will rip the rim off. I've actually done it twice, because I made a case for a friend, and forgot I had destroyed mine by trying to post-size it earlier in the year.

Great info.

 

[ChesterS]

If you removed the extractor and chambered the modified shell it would be exactly in the correct depth. This would depend on how easy it would be the remove the extractor.

 

[Dave M.]

Using my stoney point (Hornady) OAL gauge to measure my OAL of a cartridge to load into the rifling, I'm finding this measurement to be false. Once I push the bullet into the rifling and remove the modified case and bullet, I find the measurement to be much longer than what the chamber will actually take once the round is loaded. Once I load a dummy round and chamber it, the bolt will not close without force. Once it closes, the bullet seats much deeper into the case than what the measurement started at. It has me scratching my head at this point. Not that it's a big deal as I use the new measurement of the round after closing the bolt as my "In the rifling" measurement. Just can't understand why the OAL gauge measurement is not accurate. I'm actually gonna start using the Wheeler technique from now on. It certainly is the most accurate. Thoughts ? Experience ?

Check the headspace of the OAL modified case against your actual sized brass. Also, are you removing the firing pin when doing the bolt close method?
dave

 

[Dave M.]

Every bullet I use in the OAL gauge shows the same inaccurate measurement. When I load a dummy round with any bullet, that measurement is much less once I load it in the chamber and close the hard to close bolt. It seats the bullet to the "True" measurement to the rifling. I've used these OAL gauges for almost all my rifles and this is the only time I've had this issue. I'll say the rifle shoots great but I'm trying to figure out why its not been firing consistently. Second round misfires are common. Light firing pin strikes but after resetting the firing pin by lifting the bolt and locking it back down, the round fires.

If you actual case has a much higher neck tension than the modified case, this could lead to different measurements. I’d still lean towards the removal of the firing pin from the bolt.
dave

 

[Dave M.]

Using my stoney point (Hornady) OAL gauge to measure my OAL of a cartridge to load into the rifling, I'm finding this measurement to be false. Once I push the bullet into the rifling and remove the modified case and bullet, I find the measurement to be much longer than what the chamber will actually take once the round is loaded. Once I load a dummy round and chamber it, the bolt will not close without force. Once it closes, the bullet seats much deeper into the case than what the measurement started at. It has me scratching my head at this point. Not that it's a big deal as I use the new measurement of the round after closing the bolt as my "In the rifling" measurement. Just can't understand why the OAL gauge measurement is not accurate. I'm actually gonna start using the Wheeler technique from now on. It certainly is the most accurate. Thoughts ? Experience ?

Also, it’s important to remember that measuring the distance to the lands using the OAL gauge, and the hard jam using the bolt and it’s camming action, will likely be very different.

 

[284winner]

Also, it’s important to remember that measuring the distance to the lands using the OAL gauge, and the hard jam using the bolt and it’s camming action, will likely be very different.

I did all the above. The only thing I concluded is that I was the problem. I really like the stripped bolt procedure. It'll be how I do it from now on.

 

[284winner]

If nothing else, this self made screw up steered me to a better place.