Problems finding seating depth

[predatornut]

This morning I was trying to measure the C.O.A.L. on my R700 5R 300 WM with 190gr Berger vld hunting bullets. I was using a Stoney Point C.O.A.L. guage and comparator to measure to the ogive. I was getting measurements from 2.807 to 2.840. I just am lost as to why. I was using it the same as I always have and have never had any trouble getting consistant results. This is my first time loading with vlds and they didn't seem to have a stop when pushing the bullet into the lands, it felt kind of "mushy". I am just looking for a little schooling on technique for this since I would like to seat these kissing the lands to start my load development.

Thanks.

 

[MALLARD]

Re: Problems finding seating depth

i'd just load up and shoot. You'll be doing a seating depth test on paper anyways, and i think berger suggests doing .050 increments for the intial test. So that variation shouldnt be a problem since its just an arbitrary starting point.

you can load up two , COALs at both 2.807 and 2.840 , then chamber both rounds and one should show more blemish marks then the other. If they both show marks then your 2.840 is just excessive.

 

[antagonist]

Re: Problems finding seating depth

The problem, I believe, comes from the taper of the VLDs and the taper of the leade combined with the soft metal makes it almost impossible to get a consistent reading. That's the mush you're feeling. Unless you can measure the force you'll be hard pressed to get repeatable numbers. It might be easier to mark the projectile with sharpie marker or dykem and seat it to see if its touching. Then back it out or seat it deeper and repeat until you find the amount of engagement you want. Not the fastest way, but it should work.

 

[22~308TargetShootr]

Re: Problems finding seating depth

I was having the same probably about a week ago with the Berger 175 VLDs, and it was driving me absolutley nuts, I probably spent an hour and a half taking readings with the same stoney point gauge, and never came up with the same number three times in a row, I can get the same reading (or at least to within.001 or .002) everytime with my Sierra 155's that was my normal bullet. so I was perplexed, and quite frankly p&%#$@ off, so I called up and spoke with a pretty knowlegable local reloader who I completely trust who explained that was because of that secant ogive of the VLD's. He explained a way to use the stoney point gauge and a cleaning rod from the muzzle (being carefull obvisously) to attempt to get a feel for when the bullet is touching the lands, said it was a delicate process. He said it was sort of a trick and would be easier if you had three hands, but other than that he also sort of mentioned just taking the closest couple readings you get and make a decision as to a starting point. I'm no expert myself, but just passing along some of what I've been told.

C.D.

 

[predatornut]

Re: Problems finding seating depth

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: antagonist</div><div class="ubbcode-body">The problem, I believe, comes from the taper of the VLDs and the taper of the leade combined with the soft metal makes it almost impossible to get a consistent reading. That's the mush you're feeling.</div></div>


That's what I was thinking. I guess I will just load them up to the shorter length and go from there.

Thanks for the replies.

 

[Suasponte]

Re: Problems finding seating depth

Take a piece of your brass that has been fired in the rifle and cut slits in the neck with a diamond cutting bit for a dremel tool. The reason most get bad readings from the stoney pointe and hornady gages is that the brass is not properly headspaced for your rifle.

After you have slit the case neck smooth out any burs on the neck. Place the bullet you want to check and chamber it. Carefully ejected the round and place it on your Press. Run the seating stem all the way up, then Run the brass with your bullet up and slowly run the seating stem down until you feel it stop. That should set your die to seat the bullet just touching the lands.

Terry