Regarding oal cartridge measurement techniques

[Zeneffect]

I'm sure everyone is familiar with the Sinclair or hornady oal gauge, the cut up a spent case method. Looking into the tap to make my own cases for the hornady tool and I ran across this.

https://www.midwayusa.com/product/1012713931

The method described can be replicated with the required cleaning rod, orings, zip ties, tape.... many household items come to mind. why is this method not mentioned more? Is the main problem centering the projectile on the rifling accurately and repeatedly?

[Mad Charlie]

Can't say much about the FA setup, but this outfit sells the tap.

https://drillsandcutters.com/

[Trapperscott]

Can anyone tell me the thread pitch for the Hornady Lock n Load modified cases?

[Zeneffect]

5/16" 36

[Trapperscott]

5/16" 36

Thank you sir.

[Old Bob]

5/16" 36

https://drillsandcutters.com/5-16-36-hss-taper-tap/

[Oso Polaris]

The Hornady gauge is threaded 5/16" x 36tpi. You will need:
1. Drill bit size "L" or 7.3mm
2. Tap (5/16" x 36tpi)
Note: you can buy a set of above on Amazon for $15-$20. Do yourself a favor and buy both the Tap and also a dedicated Drill Bit and store them together in your reloading bench.

The challenge is a method to hold onto the case in order to drill out base and then tap the threads. If you have a metal lathe then this is child's play with either a 3 or 4 jaw chuck or collet chuck.
Other ways to secure the case is to hold it in a wood block.

This is a thread related to this topic, including resizing an existing Hornady Modified Case and dealing with a potential stuck/damaged case failure (rim separated on modified case).

http://saubier.com/forum/showthread.php?t=35504

[Trapperscott]

Thank you gentlemen for the information. I really appreciate it.

I will probably start out attempting to make a modified case by chucking a piece of brass up in my lathe in my 4 jaw chuck. For me it will be easier to dial in on my lathe than it will be to sweep it in on my Bridgeport.

I have the tool but don't have the modified cases for a few rifles that I have purchased in the last year or two. I asked if anyone knew what the thread pitch was because I was to lazy to go to the shop and dig out my lock n load tool and a thread pitch gauge. As always you guys are the best at sharing information. Thanks again.

[Zeneffect]

if you dont have a lathe a 1/2" drill chuck adapter will work to hold the brass on the cheap. about $15 on amazon. put it in a vice.. get to work. HIGHLY recommend stepping out the hole rather than going at it in a single shot, especially when using nothing but hand tools.

[Lemonaid]

Gavin of Gavintube has a vid on this for the Hornady O.A.L gage using a lathe. https://www.youtube.com/watch?v=rAkbuJk6qQE

[Growler]

[riuma]

I don't think it much matters. When you start pulling the handle the results are what they are unless you want to measure the ogive of each bullet and adjust the seating accordingly. Not being argumentative, just giving an opinion.~Riuma

[Klem]

Growler,

OAL was the convention long before Stoney Point designed their bullet-to-ogive gauge - now called the Hornady gauge.

I would hazard OAL is still used because;

• The quality of modern bullet manufacture is pretty good, relegating this concern.
• The definition of precision varies across people, guns and disciplines. Many don't know, let alone care about the difference in variation between bullet-to-tip and bullet-to-ogive. With all the more influential variables determining where a bullet goes for many it is a non issue.
• Like their headspace attachments, Hornady ogive devices are not all the same ID - this means comparing measurements across shooters is fraught. We may as well talk in terms of OAL.
• As you say, OAL includes information where mag length is concerned.

Bottom line, the variation difference between base-to-tip and base-to-ogive is a personal concern for the more particular shooter.

[Oso Polaris]

You can use the OAL gage to determine the max OAL to Bullet Tip or attach an adapter to your caliper with Bullet Diam. Insert to determine OAL to Bullet Ogee.

As Klem said different people have differing degrees of interest/use for the data.

[Growler]