ok I've got a Rem 700 wth a custom barrel in 260 Rem that I'm having problems getting consistant accuracy out of.

I've been using Lapua 243 brass and have now found I'm getting a thickening of the neck at the shoulder/neck at the necking up from 243 - 260 has drawn some of the thinker shoulder into the lower neck area.

I've been old that this may be contributing to my accuracy issues, so I have got some factory R & P Brass to try but havnt got to the range yet.

I've also just bought a Sinclaire concentricity gauge to see what sort of runout I'm getting on my reloads.

Well that been interesting, but not exactly helpfull.

I started by checking the runout on my 204 reloads as the Cooper shoots 0.3's any day of the week. Well there were a couple around 4-7 tho, but the rest were under 3tho so I'm happy with that. I then thought I'd check some 204 prep'd cases that had been neck sized by measuring the runout on the neck. These showed similar results. Most were under 3 tho, but about 6-7 out of 60 were around 6-7tho out of true.

Next I selected the best and worst 6 and seated the 39g Sierra projectile and measured the runout on the seated bullet. Well thats where it gets interesting. All of the 6 worst cases had less than 3 tho runout, and one of the best ones had 7tho runout.

Now I pulled the bullet out of the one with 7 tho and ran it through the full length resize die and re seated it. Still 7 tho. Pulled the projectile and checked the runout on the neck, less than 3 tho.

Ok I couldnt draw any meaningfull conclusions from this exercise other than wondering how am i supposed to control runout.

Now I'll get to the 260. I checked the runout on some of my Lapua reloads and most were less than 3, with the odd one over 3 tho. Then I checked the R & P loads and found much greater variance then many more over 3 tho so I'm not holding much hope that these will shoot better than the Lapua brass.

What I did notice is that quite a few of the 95 Vmax reloads have 1-2 tho runout, measured about 2/3 towards the tip, but I could see a noticeable runout in the polymer time while rotating the case in the gauge.

So now I'm wondering if the 95 Vmax's might just not be upto the grade for consistent 0.5" at 100m accuracy.

So thats the story, now the questions

1) Am I better to neck down 308 rather than neck up 243 to avoid the thickening on the inside of the neck (which will probably result in neck turning anyway), or should I just inside neck turn to remove the excess material, or should i outside neck turn to remove it, or both???.

2) is 4-8tho runout likely to have a significant impact on 0.5" /100m accuracy, or is this getting into the realm of benchrest and 0.1's?

3) What should i be looking for to minimise runout issues.

4) Are there any quality issues with the vmax's and the polymer tips being off center.

Cheers

Grant

Just what is the custom barrel that you had put on the gun? Sounds like some of the runout that you have is excessive, and could contribute to inaccuracy.

One of your runout problems could be the sizer button in your die. If your die sizes the neck down too much and you have to use a sizing button then it can pull the neck off center. My dies are set up not to oversize the necks so I do not use a sizing button and I have .003 neck tension this way. I borrowed a concentricity gauge and the worst that I found was .001 out on my Remington brass. I think Lapua is a little over rated personally. I won my third match in a row today with Rem brass.

quote:

Originally posted by NZVarminter:

I've also just bought a Sinclaire concentricity gauge to see what sort of runout I'm getting on my reloads.

Well that been interesting, but not exactly helpfull.

Cheers

Grant

Hey NZV

Looks like you are embarked upon the path of chasing concentricity!

Most of us have done this and "feel your pain". The good thing is that you will learn a lot about dies and methods by striving to reduce runout. You will find that the type of sizing and seating dies are the most important factor in reducing runout.

One method is to have special dies made like Dwight. Perhaps we could get him to tell us exactly what kind of dies he had made and how much they cost and any specifications for them.

I pretty much beat it down the barest minimum by using Lee Collet Neck Sizers and Competition Seating Dies (either RCBS or Redding) and finishing off with a Bersin Tool.

If you check the runout on a fired case neck you will find that it is zero or very close to it. The brass has expanded to fit the chamber walls which should be very concentric. If there are any variances in neck thickness the imperfections have been pushed to the inside of the neck. So you are starting with a neck that is concentric on the outside.

A Lee Collet has a floating mandrel that will not push the neck to one side or the other and has no pushing or pulling action to off center the neck. That's what makes them work so well.

A Redding Competition Seater is a very good seating die and will seat your bullet and not introduce runout.

So, I guess my recommendation would be to upgrade your dies and see what happens.

hey NZV, where did u get your Sinclaire concentricity gauge from? and how much did it cost ya? sorry its a little off topic but im yet to see one down here, maybe im looking in the wrong place/


anyway goodluck with your accuracy problem hope you get it sorted. could be your mounts, rings or maybe scope thats causing the problem? I have some leupold qwr rings or whatever they are called, and the "key" broke in the rear on is about to break in the front...

Paul,
Go the the sinclairinternational web site for lots of really neat tools for the reloader. If you have questions give them a call and get straight answers. They are all shooters.

One of my dies that I set up and the easiest is the Redding Type S Bushing die. You can buy them as singles after understanding the instructions buy about 3 of the bushings to give you a little play room. Due to wall thickness from different brass companies you may have to change bushings. I found this to be the case of Norma versus Rem. Norma is pretty but the Rem works just fine.

I personally try to get .003 of neck tension and by setting up properly for this the need for the sizing button is eliminated. That is for my 300SAUM.

For my 7mm08 that is winning matches I use the same .003 of neck tension. I stumbled on to this by accident on this. I bought a set of Forster Competition Dies and it had a neck sizer that gave me the right tension. I personally prefer FLS and a guy on this site wrote about Forster honing dies for a $10 fee. I sent my FLS die to them and asked to make it the same as the neck die. They turned it around fast and it is perfect for my Rem brass.

The only other thing that I think makes a big difference is the Forster Comp Seater die that centers the case as it seats the bullet.

I may have just got lucky but I don't have runout in my loads over .001.

Hope this helps.

NZ,

1) I would neck down .308 brass using a neck bushing sizer die, run brass over an expander mandrel pushing brass irregularities to the outside, and outside neck turn. I would not inside neck ream.

2) Each handloading step builds on itself. I do not think 4 tho runout will have significant impact by itself but every detail aids accuracy.

3) Outside neck turning and using hand seating dies will minimize runout issues.

4) I am not aware of any quality issues with vmax's or polymer tips impeeding your objective.

Cheers.

Paul,
Also check the 6mmbr.com site for a lot information. That doughnut you got from sizing up needs to be outside neck turned to remove if my memory is correct. I have not done any of that stuff yet but will when ever I get a 30BR built and at that time I will have to neck up 6mmBR brass.

quote:

Originally posted by NZVarminter:

1) Am I better to neck down 308 rather than neck up 243 to avoid the thickening on the inside of the neck (which will probably result in neck turning anyway), or should I just inside neck turn to remove the excess material, or should i outside neck turn to remove it, or both???.

A simplistic question for sure but it begs; why not use 260 Rem brass from the get-go and then all your necking up or down problems are moot?

Ditto. 260 Rem brass would save a lot of head ache and expense.