pressure

[col48]

hi all
i am going out to day to see what is the top powder charge i can safely run,
now my question,when looking for signs of over pressure is it best to measure the part of the case that is just above the extractor ring (in the recess).what size expansion can you go to 1th 2th 3th 4th i know to look at the primers and to check for extractor marks on the case,and harder bolt lift than normal.
it is on a 243 AI 270 tight neck.lapua brass fire formed.

i am asking as i have used my ballistics program to see what powder it says to go up to,and it said 49g of n165 under a 95g vld fed 210 primer.
now i have tried up to 50.2 and can not see any signs yet,
AM I MISSING SOMETHING.
so i am going to keep going till i see some signs,with the checks i have mentioned,will i be able to tell if i am going to far.
thanks
Colin

 

[James Jones]

by using fire formed brass that has only been neck sized and being that you gun is a full custom build your pressure signs will be less evident. If you go by the stickey bolt method your pressure could be dangerously high and get their fast. For micing the case above the rim in the web area I consider .004" the max and I have seen it as low as.002" and the pressure be topped out so that to is an indication that can vary from gun to gun.
I believ the best way to watch your pressure is by velocity , if your getting a velocity thats a good deal faster than most posted data the chances are that your pressure is going to be high.

 

[col48]

[ QUOTE ]
by using fire formed brass that has only been neck sized and being that you gun is a full custom build your pressure signs will be less evident. If you go by the stickey bolt method your pressure could be dangerously high and get their fast. For micing the case above the rim in the web area I consider .004" the max and I have seen it as low as.002" and the pressure be topped out so that to is an indication that can vary from gun to gun.
I believ the best way to watch your pressure is by velocity , if your getting a velocity thats a good deal faster than most posted data the chances are that your pressure is going to be high.

[/ QUOTE ]

Hi JD
I have been out today and i went up from 50.2 then 50.5 then 50.8 then 51.1 then 51.4 i did the checks as mentioned above and still no signs anywhere.now i don't want to run the gun at max,but i would like to be up there,may be thats y my groups on the other post where not as good as i thought they should be.
(well that what i am thinking anyway)
and i am finding it hard to find any data on this load,
thanks again
Colin.

 

[Centre Punch]

Col,
One of the reasons why i use USA powders is exactley like you said "there is very little data for the 243AI using Vit powder".
However check out this link:
http://www.angelfire.com/nd/243ackleyimproved/243AI60.htm
Towards the end is a table of data using Vit Powders.

Ian.

PS. Where do you shoot?

 

[col48]

[ QUOTE ]
Col,
One of the reasons why i use USA powders is exactley like you said "there is very little data for the 243AI using Vit powder".
However check out this link:
http://www.angelfire.com/nd/243ackleyimproved/243AI60.htm
Towards the end is a table of data using Vit Powders.

Ian.

PS. Where do you shoot?

[/ QUOTE ]

hi m8 thanks for that.
i shoot in notts just up the road from you in northamton.
i will take a look at it tomorrow when i have more time.
thanks
Colin

 

[col48]

right i have 2 more chargers of powder to check and then that is it, i can not get any more in the case. 51.7 and 52g of vit n165.

thanks
colin

 

[Guest]

My experence with N165 or any other is when working up a load is to look at the sd's and extream spread. When you get good #'s and velocity and the next load up gets bad #'s and little or no increse in velocity your over the top. I have used N165 in a stock ruger 25-06 with good results. The loads are beyond any published data which leads me to conclude that N165 is slower than Vhit data indicates. Most of there data is very conservitive (soft).
Old Bear