help with 'off the lands math' & input? Thanks!

[wayno1]

Rem 700 PSS 18" bbl .308

Trying to seat bullet as long as possible and work up a load.

Federal Gold Medal MAtch 168 gr SMK shows an ogive to base of 3.145"

Have the RCBS Micrometer. Followed directions - 3 times.
The 'bullet' head is a very hard steel and will not go into the lands.
got the following ogive to base measurement - 3.318"

Seated a 168 gr SMK in a Federal case, resized and lnght of 2.005, as shallow as possible.
Carefully seated the round into the chamber and carefully closed the bolt. unlocked the bolt and relocked the bolt handle once more.
I am assuming the bullet was pushed back by the lands.

Ejected round while holding the case straight without the bullet touching the rifle. Measure the ogive to base and got 3.318 "

So with 'confirmation' from both the RCBS micrometer and a dud round pushed against lands, looks like I can back off .010 to BTO of 3.308 and go from there.

Input welcome

Thanks!

 

[JGorski]

Seat those MKs to and OAL of about 2.810", you'll get much better results if you do. Trust me on this one.

 

[sinister]

Try using a Stoney Point gage and get a true length (vice jamming and interpolating after you've locked down the bolt handle).

With a factory 700 you may find that kissing the lands gives you a round longer than magazine feed length.

 

[thrusty]

I like using the Hornady overall length gauge...the Stoney Point will work as well too.
Hornady Lock-N-Load Overall Length Gage Bolt Action

You will (not may) find that the factory Remington's have a long throat.

I think (going from memory here) for my AAC-SD it was about 2.97" COL for me to get into the lands with a 175SMK. Which is well over mag-length. If you want to single feed...you're GTG though.
As such, I load just under mag length at 2.84" COL (~2.25" to Ogive for 175SMK, Hornady brass and Hornady comparator).

Your measurements of 3.318" strike me as a little odd...seem extremely long for base to ogive...even seems long for base to tip (COL).

Even more off is measurement of 168SMK FGMM at 3.145" to ogive. Maybe you forgot to zero your caliper? 168 FGMM should be in the 2.81" COL range and less than that to the ogive.

 

[Everdeeper43015]

+1 on the Hornady OLG. Cheap, easy and you get to "feel" what is going on in there.

 

[wayno1]

will try the 2.81 tomorrow. Have been wokign 2.95 and 2.80 to make them similar to the fed GMM. I use this for F class so length is not an issue.

 

[tnrednk74]

I think you need to zero out your caliper with the comparator body installed. Comparator body is 1" in length. Your ogive measurements make no sense!

 

[wayno1]

Thanks for the reply. Will check the numbers.

As for OAL length vs base to ogive, I am not subtracting or zeroing for the length of the tool. I think it comes out the same.

Getting late so am going to do a set of 2.81 with 43.0 grains of Varget. been a pretty good load at F class ranges (300,500,600) but can use some improvement.

Waiting for a Lee Collet die before I get too wild about loading too many cases. Have been neck sizing only, doing fairly well. Could be better.

 

[wayno1]

Using Sinclair hex style comparator, and didn't zero. Will redo the measurements. thanks!

 

[wayno1]

Yes, you're right.
Using Sinclair hex style comparator, and didn't zero. Will redo the measurements. thanks!

 

[JGorski]

Your measurements of 3.318" strike me as a little odd...seem extremely long for base to ogive...even seems long for base to tip (COL).

Even more off is measurement of 168SMK FGMM at 3.145" to ogive. Maybe you forgot to zero your caliper? 168 FGMM should be in the 2.81" COL range and less than that to the ogive.[/QUOTE]

Id say he didnt take off for the inch of the comparator.