More OAL questions.


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Rodahayes51
April 16, 2013, 10:10 AM
I'm working up various oal cartridges for my22-250. Going from 0.01 to 0.06 off the lands. Should I do this with each type/weight of bullet in the same rifle, or does each rifle have its "sweet spot" irrespective of bullet style?

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MtnCreek
April 16, 2013, 10:31 AM
Bullet shape will typically make a big difference in where the bullets wants to be seated. I'm a little surprised you're able to within 0.01" off the rifling and still have much bullet still in the case neck.

Lennyjoe
April 16, 2013, 10:36 AM
Yes to both. My -06 loads consist of 165gr Sierra Gamekings and 180 gr Nosler Partitions. Both like different settings off of the lans.

Rodahayes51
April 16, 2013, 10:46 AM
I can't with the lighter bullets. I'm thinking of 7mm and 30-06 also.

jerkface11
April 16, 2013, 10:51 AM
Do you have one of these? http://www.midwayusa.com/product/746974/ptg-bullet-comparator-22-24-25-26-28-30-calibers It will allow you to seat every bullet so that the bearing surface is in the same place not the tip of the bullet.

Rodahayes51
April 16, 2013, 11:14 AM
Yes, plus the OAL gauge. Thanks for your input. It's a interesting and consuming hobby! Trying to take it to the next level.

jim243
April 16, 2013, 11:22 AM
Should I do this with each type/weight of bullet in the same rifle,

Personal opinion is yes. I use a Hornady LNL OAL gauge and case for each different style bullet. When trying to find the max OAL for that bullet style in my rifle. Each rifle will be different even when the chamber is cut to SAMMI standards.

I find my best results are when I set the bullet to 0.05 inch off the rifling. It may be a fluke but it works for me.

Jim

jerkface11
April 16, 2013, 11:41 AM
Yes, plus the OAL gauge

Ok good. My rifles tend to like the same jump to the lands for every bullet. The target rifle likes the bullets to be a slight jamb fit into the rifling.

Rodahayes51
April 16, 2013, 10:59 PM
Dang. I went back and measured the lengths and you're right. The closest I can get to the lands and be seated 0.224 is 0.050 off the lands! If I go to 0.010 from the lands, I'm only seated 0.188 inch. Is that acceptable in .224 cal. Rifle? If not, I'm back to seating 0.050 off lands.

MtnCreek
April 17, 2013, 09:46 AM
Rule of thumb that most say is one cal in the neck. W/ 22-250, .224" would be considered min in the neck. Some bullets seem fussy about jump, but IMHO, most are not. Pick a standard seating depth from your manual, work up your loads, then try moving it around a little to see if it makes a difference.

mljdeckard
April 17, 2013, 09:59 PM
My first batch, loaded to listed OAL, with 38 grains of H380, right out of the book, was hitting less than 1" @ 100 from my cheap plastic rest, from my over-excited shaky hands. I doubt I will have a reason to try to improve that for a long time.

witchhunter
April 19, 2013, 09:44 PM
Be careful trying to get a consistant .001 off, bullet ogive and irregularities may put some of the rounds actually touching the lands. This could cause your pressure to spike. Just my opinion....but I don't need a caliber in the neck on a bolt action target load, it is nice, but if it shoots better.....On a hunting load, yes, but sometimes on a target gun that shoots, if it needs to be blessed with a live chicken, you have to make allowances.

Blakenzy
April 19, 2013, 09:59 PM
What is the method of determining how far from the case head your rifling engagement is?

Rodahayes51
April 19, 2013, 11:33 PM
I'm using a Hornady oal gauge and bullet comparator to get the rifle oal to lands then subtracting from that dimension.

jjjitters
April 20, 2013, 03:28 AM
I take a fired case and bump it with the sizer die(not run it through) so it lightly holds a bullet but can be pushed in with moderate pressure. I then chamber the dummy round and the bullet will get pushed in as the action locks up. Then carefully extract the round so as to not bump the bullet. I made a clamp on attachment to the jaws of my calipers so I can measure the location to a point on the bullet ogive not the tip. That gives me the maximum length to the lands, then seat in .01-.08", whatever works for the rifle. Many of my loads have worked best .01 to .02 off the lands. Others .05" or touching the lands.

StretchNM
April 21, 2013, 03:25 PM
What is the method of determining how far from the case head your rifling engagement is?

Not quite as accurate as a bullet comparator, but this method works very well, even though it uses OAL measured from the bullet tip.

This is the easiest and most accurate way I've used and/or read about:

- insert a 30" length of 1/4" or 5/16” so dowel into your muzzle (of course, use 1/8" or 5/32" for .223);
- close and lock bolt;
- push the dowel against bolt face and hold it there while marking the dowel precisely at the muzzle (use a razor blade);
- now remove the bolt from the receiver;
- take another length of 1/4" dowel, say about 12" long, and hot glue your bullet onto the end;
- insert the dowel/bullet through the action, into the chamber, and against the lands;
- holding pressure against the dowel/bullet, push the long length of dowel, from the muzzle, in until it touches the bullet tip;
- holding it there, make another mark on the long dowel with the razor blade;
- measure between the marks. This is your maximum COL (OAL) for that particular make, weight, and type of bullet.

You can repeat this procedure for each bullet make/type/weight that you plan to reload. Then you can deduct .010, .020, .030, or whatever to come off the lands. It takes about 3 minutes per bullet type to get an accurate measurement. I do them all, then mark the inside of the bullet boxes with this maximum COL. Even when I don;t load them even close to that measurement, at least I always know what my maximum is, so when I go to extending the seating depth looking for accuracy, I know how close to the lands I'm getting.

The reason you have to do each different make bullet is because, while the bullet ogive is registering against the lands, you are measuring to the bullet's tip. Again, the bullet comparator is more accurate, because it registers the lands against the ogive, BUT! in order to attain that accuracy, you must, when seating the bullet, check each bullet against the comparator each time. Since the bullet tips will vary, this will be a back and forth trial and error process for each loaded bullet. For me, the variances in the bullet tips don;t give an error factor large enough to justify the time of using the comparator. Now, if you're shooting in a competition match, well.......

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