Newbie to rifle reloading... OAL? Matching ammo to rifle?


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Vitamin G
April 15, 2006, 10:22 PM
Howdy all,
I've been reloading .45acp and 10mm for a while, and just bought a 30-06. I'm about to begin loading some 168gr loads for my savage, and I've read here and there about measuring the "lans" in your rifle, and finding a perfect OAL to get the most accuracy out of that particular rifle. I know the trick involved rubbing the bullet or case with a magic marker, or lipstick, or something like that, but what exactly am i supposed to be doing, what am i supposed to be looking for, and most importantly, why???

Many thanks

i'm also looking for some reduced power loads to teach my sister with. Does anyone have any suggestions using IMR-4064? I have 130 and 168gr bullets available currently. My manual says not to go below 45gr as a minimum. How do people create the "low power" training loads without going below minimum? Does the pressure spike somehow with "low power" loads?

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Matt-man
April 15, 2006, 11:23 PM
Some bullets are most accurate when they're loaded a certain distance from the lands of the rifling. This distance is often called the "jump" to the rifling. It's one of the variables you can play with to find the most accurate load for your rifle.

The way you measure it is to set a bullet further out than normal with not too much neck tension, then chamber the round so the bullet comes up against the rifling and gets pushed back. Then you can measure the round and that length represents 0 jump. You subtract the desired amount of jump from your 0-jump OAL to get your desired OAL.

Stony Point makes a tool to measure the distance to the lands without going through the above process... works great.

Depending on your rifle's chamber and throat, seating the bullets close to the lands might make the OAL long enough that the rounds won't fit into the magazine. This may or may not be acceptable for your purposes (you can shoot rounds like that single-shot only).

Some match bullets don't tolerate jump very well, and need to be seated within a few thousands of the lands. Many of the VLD type are like that. Others, like a lot of the Sierra Matchkings, don't seem to care about jump too much. My magazine-length 168gr SMK loads for my M1A jump quite a ways, and they work great.

DaveInFloweryBranchGA
April 16, 2006, 12:16 AM
RCBS also makes a tool similar to the Stoney point for a lot less cash. I have the one in 30.06. Works very well. If you're new at it, you're better off buying the tool than to try the do it yourselfer methods.

But before you start all that other, think about trimming brass, neck sizing and other stuff. Go back and read your ABC's of Reloading related to rifle cartridges. And if you have it, Metallic Cartridge Reloading on rifle cartridges. Lots more stuff to do before worrying about the bullet jump.

Just my .02,

Dave

charger
April 16, 2006, 06:09 AM
The above method is very good. A DUMMIE round assembled extremely long with mild neck tension being chambered as your zero line,then starting at .050"shorter work your way shorter by small increments....Problem being is that out of 27 bolts I have two that will then feed said ammunition...In your 06 you probably wont get that to magazine feed for you because the mag was meant for the 06 case and none other...The two that I got it to work in are sako's..I selected the guns strictly by coincidence in the shortest chambering the action would accomodate,thats why I have room to play. On all others except my single PPC I'm confined to cartridge guidlines.If your gun is of fast action,ie semi,pump,etc your confined to standard oal's anyway because of need to crimp into a cannelure

redneck2
April 16, 2006, 06:41 AM
take an empty case and drill out the primer pocket with a regular twist drill large enough that a small cleaning rod will fit thru. Cut a lengthwise slit in the neck with a Dremel. There should be just enough neck tension that a bullet will slip with minor pushing but still not drop out

Chamber the case with a bullet seated too deeply in the neck, then put the cleaning rod thru the hole and lightly push the bullet until it touches the lands. Slide the bolt back into the rifle and use it to pull the case out of the chamber. Now you've got a dummy that's seated exactly to the lands.

Carefully measure the OAL, and then use this to set your dies maybe .010, .020 or whatever you want. It's accurate, takes maybe 10 minutes, and it's free. I've tried marking bullets with magic marker, lipstick, etc. Too much time and effort and not nearly as accurate IMO.

If you want to change the bullet, just slide a new one in. Takes a minute or two. You'll never believe how easy it is until you do it. I keep these made up for all my rifles
Depending on your rifle's chamber and throat, seating the bullets close to the lands might make the OAL long enough that the rounds won't fit into the magazine. This may or may not be acceptable for your purposes (you can shoot rounds like that single-shot only). This is important to consider. Different style bullets from different mfgs vary greatly in the distance from tip to ogive. VLD's tend to be real pointy, so seated to mag length there may be a lot of jump.

HTH

Uncle Don
April 16, 2006, 10:05 AM
I guess I'm entirely to lazy - I've used this (and I even own a Stoney Point) and it hasn't failed me yet.

A handy way to determine proper COL is to use a fine marking pencil and a cleaning rod. Use something to make the internal portion of the threads of the cleaning rod blunt so that a tip of a bullet cannot go into the concave portion. I dedicated a cheap rod by putting a patch cleaner in and cutting it off at the end. However, even a piece of Duct tape will suffice temporarily.

With the bolt out of the gun and the bullet you intend to use placed and held up against the lands and grooves of the barrel, place your cleaning rod in from the muzzle until you feel it stop against the tip of the bullet. Mark this spot on the cleaning rod from the muzzle end. Remove the bullet and repeat the procedure (without a bullet) with the bolt in and closed. The distance between the two marks will be a very close indicator of the maximum COL for that particular bullet.

Bullet
April 16, 2006, 10:50 AM
Uncle Don

You might want to read this -

http://www.benchrest.com/forums/showthread.php?t=28867

30Cal
April 16, 2006, 02:05 PM
You guys go through a lot of trouble. I push a loaded cartridge into the chamber with my thumb. If it doesn't drop back out easily, then I seat the bullet farther in at 0.005" increments until it does drop out.

Otherguy Overby
April 16, 2006, 02:46 PM
BEWARE!!

Sometimes reduced power loads can detonate.

There's information here, but the site is a bit disorganized. It's a lot of good information to go through while you are looking. They've done a lot of experimentation with subsonic rifle loads.

Start here first:

http://guns.connect.fi/gow/nitro.html

And then just look around starting here:

http://guns.connect.fi/gow/gunwriters.html


Yer welcome! :cool:

Vitamin G
April 17, 2006, 12:15 PM
thanks for all the info so far.

The above method is very good. A DUMMIE round assembled extremely long with mild neck tension being chambered as your zero line,then starting at .050"shorter work your way shorter by small increments....Problem being is that out of 27 bolts I have two that will then feed said ammunition...In your 06 you probably wont get that to magazine feed for you because the mag was meant for the 06 case and none other...The two that I got it to work in are sako's..I selected the guns strictly by coincidence in the shortest chambering the action would accomodate,thats why I have room to play. On all others except my single PPC I'm confined to cartridge guidlines.If your gun is of fast action,ie semi,pump,etc your confined to standard oal's anyway because of need to crimp into a cannelure

I actually tried this with a 168gr boat tail sierra bullet... My manual said to load the round to 3.3" I chambered the round and several other rounds, and they all seemed to end up right around 3.190"

Should I begin making all my rounds close to 3.185 perhaps, and begin checking for accuracy? How will this effect starting loads in the future? Effects on longer bullets? Shorter?

USSR
April 17, 2006, 01:19 PM
Vitamin G,

I don't know what you're doing to end up with an OAL of 3.190". Buy the Stoney Point OAL Guage and the .30-06 modified case that you need and do it right. You will need to take measurements with both the 130gr and 168gr bullets you intend to use, as the OAL will vary according to bullet. While you're ordering, also get yourself a bullet comparator so that you can measure from cartridge base to bullet ogive, which is a much better way to determine how deep to seat your bullets in the case.

Don

Khornet
April 18, 2006, 01:30 PM
is the one sold by Sinclair. It uses a case fired in your rifle. I have found it to be quite repeatable, and have even been able to follow throat reosiion over the years on my '06. Get a Davison comparator at the same time, and you're good to go.

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