Shoulder bump / headspace question

[Dusty Stevens]

Is there a better gauge to use than that RCBS prec mic to track shoulder movement?

Yes. Your chamber. Bonus- its free and right every time. If they chamber with no resistance dont bump them even if you can. Get a fl die and keep on top of it and your brass will last longer and your bolt will be happier AND it may not ruin a trip sometime when half your cases wont chamber and you think “ man this was the time i shoulda bumped them. The ones i checked were fine tho”. Keep the precision mic in the drawer with the collet and neck dies and concentricity gage. They make good trade fodder later on.

 

[Bindi2]

In 1914 the Enfield chambers were reamed longer due to a ammunition scandal and who was awarded contracts to produce ammunition. Much of this early war ammunition would not even chamber so the chambers were reamed larger in diameter and longer to the chambers shoulder to chamber the bad ammunition.

And since the British were still angry over our American disagreement with King George the Brits never told the SAAMI when it was formed in 1926 about the chamber changes. We got even and changed the rules of Cricket and Rugby and called it Base Ball and Foot Ball. Then the British got even with our changes and called Soccer foot ball and caused mass world confusion.

And at least you Ozmaniacs were smart and hired the American firm of Pratt and Whitney to setup your Lithgow Enfield plant. But sadly you cheated at Perth and took the Americas cup from us and Men at works song "Down Under" almost became your National Anthem.

You might remember me under another screen name at Gunboards Enfield forum and my free Enfield books and manuals. I miss all the fun I had with you Australians especially Dr Beers. I once asked him for Enfield pointers so he took a photo of his target pointing with his index finger. And I see Alan De Enfield likes to use all my old photos and images.

Yes ED i knew who you were instantly.

 

[Bindi2]

Yes. Your chamber. Bonus- its free and right every time. If they chamber with no resistance dont bump them even if you can. Get a fl die and keep on top of it and your brass will last longer and your bolt will be happier AND it may not ruin a trip sometime when half your cases wont chamber and you think “ man this was the time i shoulda bumped them. The ones i checked were fine tho”. Keep the precision mic in the drawer with the collet and neck dies and concentricity gage. They make good trade fodder later on.

Actually throw the FL die in the bin that is where it belongs. The Lee neck collet die is what you use and a BODY DIE when they start showing resistance to bolt closure. set the die so there is MINIMAL shift in metal. I have been reloading 303 since the early 70s, my go to work rifle is a 303 using approx. 100+rounds per week. I have learnt a few tricks and other things about the 303. I range shot with them until it was phased out. I have used just about every type manufactured as well as most calibre conversions done on the 303 case. I still own several calibre conversions and number of military spec rifles. It is a rimmed case in a very generous military chamber made to work in all conditions every time with no thought to saving brass for reloading. It is not a target rifle with a tight chamber using reloads on a day every now and then.

 

[JFrank]

Ed you just showed that SAAMI specs for the 303 Brit are wrong which has been the major problem all along. Don't FLS unless you absolutely have to the dies are wrong, use a Lee neck collet die. As long as the bolt does not close on a 74 gauge you are good to go. Making a tight 64 is just as bad as a closure on a 74. Relax head space is in your head it is being used as a means to get rid of many serviceable rifles.

In 1914 the Enfield chambers were reamed longer due to a ammunition scandal and who was awarded contracts to produce ammunition. Much of this early war ammunition would not even chamber so the chambers were reamed larger in diameter and longer to the chambers shoulder to chamber the bad ammunition.

And since the British were still angry over our American disagreement with King George the Brits never told the SAAMI when it was formed in 1926 about the chamber changes. We got even and changed the rules of Cricket and Rugby and called it Base Ball and Foot Ball. Then the British got even with our changes and called Soccer foot ball and caused mass world confusion.

And at least you Ozmaniacs were smart and hired the American firm of Pratt and Whitney to setup your Lithgow Enfield plant. But sadly you cheated at Perth and took the Americas cup from us and Men at works song "Down Under" almost became your National Anthem.

You might remember me under another screen name at Gunboards Enfield forum and my free Enfield books and manuals. I miss all the fun I had with you Australians especially Dr Beers. I once asked him for Enfield pointers so he took a photo of his target pointing with his index finger. And I see Alan De Enfield likes to use all my old photos and images.

Too bad you fellas don’t have a flavored coffee to share .

 

[Bindi2]

Too bad you fellas don’t have a flavored coffee to share .

I drink scotch and use 303s.

 

[Uncle Ed]

Too bad you fellas don’t have a flavored coffee to share .

Sharing a cup of coffee is better than sucking on lemons and writing bitter posts.

My apologies, for running into a Australian I haven't heard from in years.

 

[JFrank]

Actually I thought it clever and far from bitter but each to their own

 

[Coyotefurharvester]

Uncle Ed I tried the spent primer method on my new custom reamer chambered 22-250(2). Showed exactly 0.002 headspace which matched the go,no go measurements the gunsmith provided for each rifle. Going to try it on a buddies 7mms rem mag when we set it up for an elk hunt.

 

[Uncle Ed]

Uncle Ed I tried the spent primer method on my new custom reamer chambered 22-250(2). Showed exactly 0.002 headspace which matched the go,no go measurements the gunsmith provided for each rifle. Going to try it on a buddies 7mms rem mag when we set it up for an elk hunt.

At lower chamber pressures like in a workup load or reduced loads the primers always protrude from the base of the case. This is because the chamber pressure is not high enough to make the case stretch to meet the bolt face. My 30-30 always has the primers protruding at 38,000 cup or 42,000 psi max chamber pressure.

P.O. Ackley did a experiment with a 30-30 Imp and removed the locking bolt from the Winchester 94 30-30 and remotely fired the rifle. Nothing happened because the cartridge gripped the chamber walls and the base of the case did not stretch to meet the bolt face. Meaning no bolt thrust load on the bolt face and why you do not want any oil or grease in the chamber before firing.

I think of the spent primer method as the cheap bastards headspace gauge. I collected old milsurp rifles and didn't want to buy headspace gauges for all these old rifles so I used the primer method to find out how much head clearance each rifle had. And on a rimmed cases if you add the rim thickness to your head clearance you will have your actual chamber headspace.

 

[Webster]

Novice reloader...

Virgin adg brass was .012 - .014 less than saami (zero) using the RCBS precision mic guage.

After fire forming at a minimum charge (seating depth test, mainly to fire form), case grew .007 and now measured .006-.007 under the zero on the saami headspace guage...assuming zero is saami minimum on that precision mic headspace guage, they have not expanded out even to min saami specs yet?

Assuming these may not be compeltely fire formed based off the light charge. Should I just load them up and shoot them again or take that .007 less than saami and bump it back .001 and maintain that headspace?

They empty cases still chamber fine in a stripped bolt.

Your cases don't have to conform to SAAMI specs. They fit your chamber.

 

[Vandy321]

Your cases don't have to conform to SAAMI specs. They fit your chamber.

Understood, was just using saami #s as a reference on that gauge for how much my brass grew during fire forming

 

[Vandy321]

I'm getting about .004 averwge over 10 cases with the headspace measurement using a spent primer. Trice fired brass...does it have more to grow? Brass chambers fine, no need to bump yet.

Does a belted mag take 3-4 firings to fireform?

Would it be beneficial for my notes to get the reamers deminsions from the smith?

 

[JFrank]

Reamer prints are a good thing
No bumping yet, go at least once more