Max Overall Cartridge Length

shrpshtrjoe · Posted: Sat Mar 05, 2005 1:52 pm Post subject: Max Overall Cartridge Length

Howdy. How do you find your max overall cartridge length there are a few different methods. The way i find it is by slightly resizing the case and slightly seating the bullet in the case and then chambering the round . Then removing the round very easy and then mic it, i do this until i get a fairly consistant measurement. Then i back it off 15 thousanths . Then start shooting and ajusting the depth from there when i find the proper depth for that bullet i make a dummy round and mark it with the depth for future ref. How do you guys do it. Question

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

Hello again,
My method is probably way too complicated and cumbersome, but I know it works. The first thing I do is measure the magazine to see what my maximum OAL can be. then I subtract .030" from that to ensure that there will be no problems feeding rounds into my chamber. This gives me my "drop dead" (absolute longest) OAL. I then take a "fire-formed" case from my gun and crush the neck VERY slightly so that it will hold a bullet. Next I start a bullet into the case just enough so that it stays there. Take a black "magic marker" and completely paint the exposed bullet. I then carefully load the shell into the chamber and close the bolt. (Don't trip the trigger or your measurement will be way off.) Open the bolt slowly and remove the round. If the bullet is still in the case, check for rifling marks. If they are present, the lands have seated your bullet so just simply mike the round and subtract the amount you want the bullet to set off the lands, and that is your OAL. (At this point, if there are no rifling marks, the throat is too long to use your rifling as a measuring point. Simply use the "drop dead" OAL you calculated above as your OAL. ) If the bullet is stuck in the rifling, gently tap it out with a cleaning rod from the muzzle end. Without wiping off the ink, stick the bullet back into the case and push it down just to where the ink line is . Proceed as you did above (Be sure to subtract the amount you want the bullet to set off the lands) and you have your OAL. Compare this OAL to the "drop dead" OAL you calculated above to be sure you're not exceeding it and you're good to go. I then adjust my bullet seating die and using an un-primed case, I seat a bullet to this exact OAL and write on the side of the case the OAL & exact bullet used. I then set aside this "dummy round" for future reference. There, is that clear as mud? Confused

P.S. I have been thinking about getting a Stoney Point OAL gauge, but at this point I've got most of my AOL's established, so I'm not sure it will pay for itself.

Blaine

BenB · Rookie Member Joined: Feb 01, 2005 Posts: 10

Sounds to me like you both have good working methods. I use a similar method. I have used the Stoney Point tool (borrowed) and it works well also. In as much as any of our methods only provide a starting point for finding the correct seating depth, I really doubt that the purchase of an extra gadget would be of much value to your loading procedures. However it would contribute to the handloaders ultimate goal, â€œhe who dies with the most toys, winsâ€. Laughing

Knifeboy · Posted: Mon Mar 07, 2005 1:52 pm Post subject: Re: Max Overall Cartridge Length

Well Blane,
Sounds like you really took some time to figure this whole thing out.
Thanks for the info on this both of you.

Knifeboy

Coyote_Hunter_ · Posted: Thu Mar 10, 2005 1:46 pm Post subject: Re: Max Overall Cartridge Length

It varies by gun. Some I just seat to the cannelure and crimp. (.375 Win, .44 Mag, some .45-70). Some loads for my Marlin .45-70 are determined by the maximum length that will cycle from the magazine to the chamber and then eject. Others I use a Stoney point OAL gauge (.22-250, .257 Roberts, 7mm Mag). My new Ruger .300 Win Mag has such a long throat I seat as far out as I can for the magazine.

calsibley · Super Member Joined: Jan 28, 2005 Posts: 317

I also use the Stoney Point OAL guage and like it. There is a slight learning curve involved, but you catch on quickly. The secret appears to be in using a light touch. Don't push hard to get the bullet tight into the lands or pressures can skyrocket on you. With todays rifle chambering I find there are some rifles where you can't even begin to touch the lands. You'd think the manufacturers had never even heard of SAAMI, muchless adher to their guidelines.

I think you have to remember that not all rifles shoot best with the bullets into the lands. Some seem to prefer a jump to the lands. I never worry about a round being too long to clear the magazine. Most of my shooting is at the range, and I load everything single shot anyway. Best wishes.

Cal - Montreal

WildHorse · Member Joined: Feb 17, 2005 Posts: 184 Location: Nebraska

Ditto on the Stoney Point Gauge. I couldn't live without mine.

shrpshtrjoe · Posted: Sun Mar 20, 2005 3:50 am Post subject: Re: Max Overall Cartridge Length

Howdy. Just ordered the stoney point gauge. My method works well just takes more time, but it seems im turning into the reloading center for all my buddies, and the stoney point gauge should be quicker than my method and should eliminate any second guess's

calsibley · Super Member Joined: Jan 28, 2005 Posts: 317

Hello Joe,

There's nothing wrong with the method you originally described. Many reloaders use it and are quite satisfied. This can be a frustrating task though because all bullets simply aren't the same length. I've noticed a difference even in the same box. It shouldn't matter much though since the length is only critical to the ogive. I've also got the RCBS Precision Mic for a couple of calibers but rarely use it any more. Isn't it amazing the variety of stuff we end up with for reloading? When I pass on and leave all this stuff to my son I imagine he'll spend many an evening just sitting there scratching his head in wonderment. Best wishes.

Cal - Montreal

shrpshtrjoe · Posted: Mon Mar 21, 2005 7:20 pm Post subject: Re: Max Overall Cartridge Length

Howdy cal. I agree i am comfortable with the method i described but as i load more for other people i would feel better with the stoney point gauge the last thing i want to do is get it wrong. I think the gauge will eliminate any doubt.

BillPa · Member Joined: Mar 17, 2005 Posts: 89

I use the Stoney Point tool with a few modifications. I make my own inserts bored .002" under the bullet ogive to get hopefully a more accurate measurement. Another trick is to use two gages, one on the bullet ogive and one on the base to accurately measure the bearing length of the bullets. You can sort bullets based on this measurement.

In addition to the bullet inserts, I also make some in 27,30 and 40 degrees to measure the headspace so I can bump the shoulders back .001". Its not a actual measurement, but a realitive one that I record for each rifle.

Anyone wanting to modify their own cases, the thread is 5/16-36. You can get the taps from MSC and use a .297" bit to drill out the primer pocket. The necks can be opened up using some 320-400 paper.

shrpshtrjoe · Posted: Wed Mar 23, 2005 3:13 pm Post subject: Re: Max Overall Cartridge Length

Howdy Bill. Welcome to huntingnut. Thanx for the tips. My gauge should be here tommorow and i will see how it does.

shrpshtrjoe · Posted: Fri Mar 25, 2005 12:48 pm Post subject: Re: Max Overall Cartridge Length

Howdy. Got my stoney point gauge and tried it out . Much quicker and easier than my other method i can't believe i waited this long to get one. Much impressed with it.

slamfire · Rookie Member Joined: Feb 07, 2005 Posts: 19

I use a flat based bullet inserted into the case point first. After chambering it gives an accurate head to land measurement.

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

Slamfire,
How do you use this "head to lands" measurement after you find it? Won't this measurement be different for each different bullet depending on the ogive? Do you use another gauge (StoneyPoint or similar) to find your OAL for each different bullet? I've been considering a Stoney Point, but don't want to invest in all those "modified cases".

Blaine