seating depths, for the love of god.

[Tikkat1x]

so all of a sudden ish, my seating depths are all over the shop, its not something iv had problems with in the past but the last 2-3 months on my 223 69gr sierras i set it for 1.855" then the next one is 1.865" then 1.842", then a couple back around 1.855" then some anywhere in between, i very nearly just took the sledge hammer to my press and dies, the press is a RCBS summit, only a few months old, and redding dies, dies is set correctly, i have to right shell holder, it happened a bit ago on my 243 bullets and i worked out the die had some how worked its way down a bit and was nigh on touching the shell holder, put that right and it worked a treat, now this time its the 223 and its its all ***** up, what on earth could be causing this ??? my lats press was a rockchucker, same dies, but a Hornady comparator set, now i use a derraco comparator set,

thanks.

Lee

 

[Cyres]

What charge weight are you using. ?
I had similar issue once due to a mixed batch of Lapua brass with different case capacities so some were compressed and COL changed.
I can't remember my COL as reloading data book is not too hand.
D

 

[Tikkat1x]

23.5gr of N133, hornady brass, bought once fired, not fired x4, i can hear a crunch when seating them, only just though,

 

[Apthorpe]

i very nearly just took the sledge hammer to my press and dies,

Owing to sod’s law, I can almost guarantee that, given the above, the brass would be at fault.

 

[ColinBr]

Possibly as above then mate with a compressed load.
I was getting that when doing my load development for the 6mmXC last week using copper bullets as the charge increases, so did the compression, and I was getting a variance in seating depth.

 

[palo]

As others have said it's probably the compressed load.
Load a few dummy rounds without any powder or primer in them and measure them to see .

 

[Tikkat1x]

bleeding viht has me no where near a compressed load, 25,9gr is max

23.5gr of N133, hornady brass, bought once fired, not fired x4, i can hear a crunch when seating them, only just though,

sorry, N140. was just replying to another thread about n133, must of got mixed up,

 

[Tikkat1x]

Owing to sod’s law, I can almost guarantee that, given the above, the brass would be at fault.

how come

 

[Tikkat1x]

As others have said it's probably the compressed load.
Load a few dummy rounds without any powder or primer in them and measure them to see .

good plan

 

[Sniper308]

Sounds like compressed loads to me. Take 0.2 off and see

 

[Lateral]

Is it seating depth, or varying bullet lengths ?

I find that bullet lengths can vary a lot, particularly plastic tip. So I measure a few bullets to get an average, load and then only measure of the ogive, which is always consistent.

 

[Tikkat1x]

I’m going to measure some bullets tomorrow. And I always measure off the ogive

 

[MilesW]

Can someone explain how, with a correctly set up seating die, a compressed load affects seating depth. Excluding the obvious of a case absolutely chock full.
It does not appear the OP's stated load is compressed anyway, according to any data I have access to.
Three things to look at.
Primer seating depth. Is the measurement consistently off the rim or a slightly proud primer?
No vertical movement of the die relative to the shell holder/turret. Is the lock nut snug? The gap between the die and shell holder should be negligible.
Function of the die. Are the internals spotlessly clean and free of any burrs/rough spots that could impede smooth and consistent operation?
The most accurate measurement is off the ogive and the Derraco comparator is a good piece of kit.

 

[Cottis]

How old is the brass and how many times fired without being annealed?

Easy to check by seating some bullets in dummy rounds with powder/primer but annoying to have to pull bullets afterwards.

If you really think it's due to compressed loads, cover the top of the charged cases and knock them against something to encourage the powder down away from the case mouths. Should give you a touch more space that will confirm if that is indeed the issue but I'm with Miles above. Unless you have powder almost spilling out the top of the case, I would be surprised if a few kernels of powder were effectively stronger than a couple of though of neck tension and interference fit of brass/bullet

 

[Foxyboy43]

Hmmm.

“223 69gr sierras i set it for 1.855"
“sorry, N140. was just replying to another thread about n133, must of got mixed up”.

Your 23.5 gns of N140 load is actually just below the minimum of Viht’s data so the powder charge will definitely not be compressed - unless of course you are seating the bullet very, like very, deep.
As you can see Viht show a COL of 2.244” against your 1.855” (Viht’s show a case trim length of 1.752”) so either I am missing something profound (highly possible this time of day) or you must have some considerable upper arm strength! If your reloaded round looks like a Sabot there is definitely something amiss!
Maybe have a look at your reloading data - especially COL…..

 

[Utectok]

Try a drop tube that usually gives a fair bit more room

 

[MilesW]

As you can see Viht show a COL of 2.244” against your 1.855” (Viht’s show a case trim length of 1.752”) so either I am missing something profound (highly possible this time of day)

Maybe the bit where he says he measures at the ogive with a comparator...

 

[Foxyboy43]

Maybe the bit where he says he measures at the ogive with a comparator...

Doh!
I did say it was very early - that and old age.
Nurse!!!

 

[Apthorpe]

how come

It was half tongue in cheek. If you smashed up the press and dies, it's sod's law that some other element would be at fault.
More seriously, and based on a series of suppositions which might be wrong, I suspect the brass because it seems like this is a new problem with equipment that you'd previously found adequate. Personally, I won't use Hornady brass because it seems to have a patchy reputation (and bought as a component is far too expensive for its apparent quality), and if you've bought it "once fired" there's no way to be sure it hasn't been fired several times.

 

[fizzbangwhallop]

Is it seating depth, or varying bullet lengths ?

I find that bullet lengths can vary a lot, particularly plastic tip. So I measure a few bullets to get an average, load and then only measure of the ogive, which is always consistent.

As Lateral says…. when it was still possible (simple) many years ago, I imported a few 100 Nosler 6mm Ballistic Tips and the seller broke down the boxes with the bullets in a plastic bag for ease of posting.

I discovered when loading these later that not all bullets are made the same (different machines?) and was getting a variance in seating depth which drove me nuts to a point.

In the end I just loaded them and never had a problem, if there was a variation in POI it was minimal and there are too many other variables that will affect your POI outside of straightforward target shooting when you strive for the same position with every shot.

Having switched to the very nice Derraco comparators… there’s always the chance that the hole in the middle is different to your previous comparator My ShootingShed comparators in .20 & .223 are different to the original StoneyPoint versions. So it was a case of re-measuring chamber length etc from scratch to maintain consistency.

Cheers

Fizz