OAL Variance

[Blue Streak]

I put together some 30-06 rounds yesterday for my Garand and I saw a +/- .004 variance in my OAL after my seating usung a regular Hornady seating die. (using 168 gr. Hornady HPBT match bullets)

I checked the length from the tip of the bullet,..which we all know varies but I also checked the lengths from the Ogive,..which also varied.

The brass was all LC military, but not all the same lot / year.

Is this variance due to my brass? I though one reason for my variance could posibly be different rim dimensions in the brass??? Also, would a competition seating die help remove this variance? Need some help figuring this out.

Thanks for the advise.

 

[doc76251]

Re: OAL Variance

A couple of things to consider about OAL out of standard dies.

Not many of them seat the bullet with anything other than by pushing on the nose of the boolet, depending on the boolet itself of course.

Your brass will certainly have an effect.

As you have noticed the OAL of the boolets will vary from boolet to boolet.

Depending on the powder fill inside the case, some times you will encounter "push back" where the boolet actually pushes back out.

The most common cause I see is inconsistency in the stroke of the operator when seating. You can vary your depth significantly by how you run the ram.

The comp seater will not help any of the above but it will allow you to seat them a little long on the first go around and then come back through after measuring and adjust exactly to the depth needed.

Cheers,

Doc

 

[Fuzzball]

Re: OAL Variance

No rifle cares where a bullet tip/meplat hangs in space, all that matters is how far the bullet has to move before contacting the rifleing. That is controlled by the press and seater die plug and operator consistancy, not the make, age, trim length or brand of the cases we may use.

 

[MALLARD]

Re: OAL Variance

+1 doc and fuzzball

 

[JSTARSZ]

Re: OAL Variance

I am measuring fool when it comes to reloading but the one thing I have come to find out is that +/- in small amounts doesn't change my points of impact. What changes more than anything else is powder charges thrown inconsistent. I am not a Bench Rest shooter so these small amounts of change in OAL just are nothing to get in a bind over. IMHO

 

[Blue Streak]

Re: OAL Variance


Good advise gentlemen,. thanks.

I think I may have an issue with how consistent I "stroke" my ram,....and I do mean my reloading press,..hah.

I use an old RCBS rock crusher and I can tell its beginning to get a little slop in it so I probably need to pay a little more attention as far as how I operate the thing.

I also think the old military brass I'm using still has some affect on that because I can tell that some of the brass puts up more resistance as I seat the bullets,. probably out of round,..wall thickness issues, etc,. etc.

 

[jbell]

Re: OAL Variance

I have to agree with the above posts about varying the down force placed on the handle at the bottom of the stroke. I have found on new (quality) presses you will not see any diff. but after several thousand rounds the pins and holes in the pivots will wear and varying stroke length will come into play. So watch your OAL when your press get some time on it. My Redding Boss is about 10 years old now and has had the pins replaced 1x already and is in bad need of pins and bushings agan but with some pratice you can get very consistant OALs. But in all actuality keeping the OAL variation to zero only helps the nut behind the trigger.

 

[Blue Streak]

Re: OAL Variance


Yep, Jbel, you make some good points.

I've been putting off a new press for some time. I've used and abused my old RCBS. I've thought about getting one of those new redding presses,..they look like quality equipment.

I'll keep up with my old press for awhile and just slow down and focus on my use of it for the moment to see how / if things improve.

Thanks for all the comments.

 

[TacticalRem]

Re: OAL Variance

Blue Streak,
I have a Forster co-ax press and love it. I agree it seems all bullets, even the Match grade seem to vary and since I am trying to get the most out of my rifle I measure each one from the ogive. I always start long and adjust the die to reach the optimum length for my gun. I'm seating .010 into the lands and my gun seems to like this setup.

 

[VKC]

Re: OAL Variance

As above, plus the amount of variation you are getting isn't going to result in a significant difference in accuracy.