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View Full Version : How do YOU find the longest OAL for your rifle...



Critter Control
08-04-2009, 11:38 PM
I have been reloading for a month or so and was reading about "bullet JAmming" to find OAL and was wondering if my technique is okay, and also how you do it yourself.

For me i start a bullet by barely seating it in the case, and then put it in my gun and close the bolt, if the bullet gets stuck i use a rod to knock it out and seat it a little deeper next time. i do this until i can close the chamber without the bullet being left behind. once i do this i put it in my RCBS precision mic and find the ogive length for the bullet. After that when seating the bullet into a live case I start with it backed out a little, and then slowly work it deeper until it reads the same measurement on my precision mic. I hope this makes sense, but if not please ask any question and i will try my best to clarify. Also, what do u guys use to measure the ogive? one guy i know uses a thing that goes over the bullet and rests on the ogive. i think its a stoney point too, but it has a holder like thing built into the caliper.

Well guys please enlighten me, any knowledge is greatly appreciated and accepted.


Thanks,
Kory

mike in co
08-05-2009, 12:09 AM
this is the competition benchrest forum, and some how i'm betting if you have only been reloading for a month , it is not a benchrest rifle.

this is best asked on the factory forum.

an answer here would be based on a competiton rifle, custom chamber, and on and on....

your doing fine up till you pulled out the rcbs mic.

just remember it i snot the actual oal(except for magazine considerations), its where the bullet(ogive) hits the lands. production bullets vary a bunch in tip length.

mike in co

Critter Control
08-05-2009, 12:58 AM
Well ive been trying to get into benchrest ground hog shoots with my .204 ruger target rifle and an xr-100 in 22-250. I also have a savage LRPV in 6mm norma BR on its way after the wrong gun was ordered. But how do u reload for your length Mike? I just use the precision mic because it uses a measurement at the ogive.

Thanks,
Kory

Al Nyhus
08-05-2009, 05:55 AM
Hi Kory.

Seating a bullet long and closing the bolt is a good way to do this. It's best to remove the firing pin assy. from the bolt so you get a better feel for what's going on. Polish the bullet with some 0000 steel wool and you'll be able to see the rifling marks very easily. Adjust the seating stem .010 and repeat the process...you'll see the rifling marks getting less pronounced as the bullet is seated deeper. As the marks start getting faint, adjust in .005 increments. When the marks just disappear, you've found your 'zero' point for your seating stem length...now you can shorten the seater to 'jam' or lengthen it to 'jump' from this 'zero'. Repeat this process for each different bullet you're working with. Check it periodically to see how far the throat is moving so you can compensate by adjusting your seating length.

OOOO steel wool, a dark colored Magic Marker or some DyKem all work well to help you see the rifling marks.

Hope this helps. :) -Al

SGJennings
08-05-2009, 07:14 AM
My 47 year old eyes benefit from using a magnifying glass in addition to the 4ought steel wool.

mike in co
08-05-2009, 08:12 AM
all of this so far gives you a cartridge with a seated bullet. you need to measure to the ogive of your bullet, not the plastic thing on the rcbs mic.
i use stoney point tools, sinclair carries a couple of tools, they all are used with a caliper.


mike in co

alinwa
08-05-2009, 02:15 PM
Color your bullet with a silver sharpie to really see the land marks.

jbr6mmdasher6
08-06-2009, 08:34 AM
i do the same as you silve sharpie black sharpie they all work but i get my lenghths the same way

Critter Control
08-08-2009, 04:03 PM
Thanks guys. That helps a lot. I guess i know what to do now.

Thanks Again,
Kory