Seating depth / Nosler bullets

[Mike6158]

Howdy,

I've been checking the distance to the lands in my VTR (.308) with a Stoney Point gauge. I plan to load two different bullets (maybe).

Nosler 30150 150gr Sptizer (green tip)

and

Sierra 2130 150gr Spitzer Pro-Hunter

The Sierra's are no problem. The Sierra manual says C.O.A.L should be 2.750. I consistently get 2.894 to the lands with the Stoney Point gauge. I'm going to load them .020 off of the lands so I'll end up loading them 2.874 (.124 longer than the manual recommends and .064 longer than SAMMI max in the Nosler manual)

The Noslers haven't been so easy. The Nosler manual says the SAMMI max O.A.L. is 2.810. I consistently get 3.017 to the lands with the Stoney Point gauge. Sticking with .020 off of the lands I would normally load the bullet 2.997... that sems to be a long round for a .308. It's nearly a 1/4" longer than SAMMI max.

This is a new rifle and new caliber for me. I have been loading .270 and I've measured the distance to the lands a gillion times. I started with .020 off the lands in my .270 and it seems to be a good choice.

(A) Should I be worrying about the round being a little over 1/16th of an inch longer than SAMMI max (Sierra bullets / Nosler data) or just load it and shoot it?

(B) Should I forget loading the Noslers off of the lands and just go with the SAMMI max recommendation in the Nosler manual?

PS- for those that think that the VTR is ugly... put an HS Precision stock on it. It's purdy with that stock. Kind of like a gun version of a boob job. I can't figure out why Remington put a Dollar General / Walmart stock on that gun...

 

[Mike6158]

Apparently aliens kidnapped me and removed most of my brains while I wasn't looking. I have Precision Mic gauges. Setting seating depth is a breeze with those. I was over thinking the problem into existence. I'm happily loading 50 rounds for the range... all at .020 off of the lands...

 

[royinidaho]

I'd consider shoving the SAAMI stuff to the back of my mind for later use and follow this article for any bullet seating task. http://www.longrangehunting.com/articles/vld-bullets-accuracy-1.php

 

[Mike6158]

Thanks Roy.

I went to the range today with- A new rifle, a new scope, new brass, and new bullets. New to me anyway. I had loaded 50 rounds fairly conservatively and I ended up shooting 40 of them.

It's going to take me a while to get there but I do have a question or two at the end.

I had 3 rifles to sight in. (2) brand new AR-15's with 18" Shilen match barrels and my VTR in .308. The AR's have a Leupold AR series (2x - 9x) scopes on them and the VTR has a Leupold Mark IV 4.5x - 14 x 40mm scope on it. Optics wise I'm happy with the Mark IV at 100 yards and eh.. at 200 yards. I'm not liking the AR scopes at all. They'll be ok hunting at 100 yards and less but I doubt I can shoot them accurately beyond 100 - 150 yards. We'll see. I didn't try them at 200 and I was at the range a pretty long time. It rained all day and it was windy so by the time I got to the AR's I wasn't feeling very "accurate".

All AR brass was neck turned, trimmed .005 under, primer pockets were trued, flash hole was deburred, FL sized and I used the C.O.L in the manual since it's an autoloader. FWIW... I'll reuse the neck turned brass but I doubt if I neck turn anymore for the AR's.

I used nickel plated Remington brass for the .308. All brass was trimmed .005 under, primer pockets were trued, flash hole was deburred, FL sized. I checked neck concentricity and selected 50 pieces of brass that had less than .002 runout. Most was under .0015. So I didn't turn the neck.

I used a Sierra #2130 150gr Spitzer Pro-Hunter bullet and loaded 42.2 gr (exactly) of H-335. I used WLR primers. The load was not book max. C.O.L. of the bullets was 2.734. Sierra manual said 2.750 <--- we are getting close to my point and questions

If I said that my groups sucked that would be being kind. I had a lot of fliers. At 100 yards and even at 200 yards I would get a sub-MOA group and then the group would deteriorate to 2 MOA or worse. Could I take these hunting? Sure... Nothing I shoot will be outside of 200 yards... but I don't reload and do the things that I do to shoot 2 and 3 MOA groups. I'm sorry to say that is the "norm" for the range I go to and I have never been too keen on being a part of the "norm".

My self-analysis says that my bullets were way too short and that's what was causing the shotgun like pattern on my targets. I used two different methods to determine the distance to the lands. One of them is obviously not a good choice but it's the one that I used. I used an RCBS Mic gauge to determine distance to the lands. It comes with a little "squishy bullet" that supposedly will give me a reference to the distance from the bottom of the case to where the ogive of the fake bullet contacts the lands. It's worked well for me with my .270 but I think it let me down with the .308. For one thing, it directed me to seat UNDER the Sierra manual recommendation. That should have sent up a red flag but it didn't . Duh.

The Stoney Point tool gave me very consistent results with the bullet I was shooting. In my VTR the length was 2.894 to the lands 7 out of 10 tries. Very close on the other three. I didn't use it why? No clue... Too much confidence in the squishy bullet I guess.

My plan is to follow the procedure outlined in the link that Roy included above. I'm going to load a dummy round to 2.894 and then use my Mic gauge on it to determine seating depth. From there I'll load in increments and shoot those until I get acceptable groups. I can shot sub-moa at 200 yards with my dead stock .270 and a 3-9 vari-x III leupold scope. Wood stock. No bedding blocks. Nothing fancy... I should be able to do the same with my VTR/HS- Precision Stock/Gee whiz 14.5x scope...

Anyone have any thoughts on my plan?

Going with the article Roy linked above if I go off of COL I'll end up with loads that are (C.O.L.):

2.884"
2.844"
2.804"
2.764"

How does that sound. It frankly sounds long to me. Dunno though.

One thing that I do know... I ain't loading short again... and I'll pay more attention next time. The reality is that I made a stupid mistake...

Thanks in advance

 

[royinidaho]

You are doing way more measurements than I can keep track of. That would drive me nuts.

A simple way to determine COL to the leade is to.

1. Select a full length resized case.
2. Cut two slots in the case from mouth to base of neck. Dremel tool/cutter works best for this. Slots will be opposite from each other. Hack saw is a bit much.
3. Seat a bullet by hand if possible. If not possible seat with press but just start it. Then by hand wiggle it as you finish seating it.
4. When you "think" it has about the right neck tension pull the bullet out so that there is "just" enough in the neck to hold it.
5. Chamber the dummy round slowly don't slam it home.........
6. Slowly remove the the cartridge holding it straight with a finger so that the ejector doesn't push the cartridge to one side causing undue marks on the bullet.
7. IF: the bullet remains in the chamber, there is insufficient neck tension.
8. THEN: Hold the barrel vertical and drop a smaller caliber bullet down the tube base first. A 60 gr .222 does well for me in a 270 cal. (Running a rod from muzzle to chamber gives me the vapors.)
9. Increase neck tension a bit.
10. GOTO step 5
11. When the bullet comes out with the case and neck tension is right you should marks where the leade has be touched should be visible.
12. Measure with your stoney point and you have the length to the rifling.

Load 3 and shoot 'em. If the groups aren't what you want, shorten the COL. If the groups shrink keep shortening until they expand. You then have the best COL for that bullet and load after returning to the last COL that produced good groups.

If the groups immediately increase, increase the COL from the original setting and see what happens.

Warning, seating too long MAY cause a bullet to remain in the rifling when the case is extracted. If this happens on a hunt it will certainly erk your nerves. Been there done that. This will most probably necessitate use of a rod to remove the seated bullet.