243 AI pressure problems

bogwelly

Well-Known Member
I cant seem to get consistance in the ammo pressure wise, the accuracy is fine but!
i have done the load development and thought i had it sorted at 44gr N150 behind a 70gr blitzking
I fired 20 shots today and probably 12 were fine, 8 have soot marks down the neck and onto the body,5 had small marks on the head from the ejector 2 had blown the primer out alltogether and 1 has blown the primer and had bad marks on the head from both sides of the ejector mechanism
I measure each powder charge out to within less than a 10th of a grain
Someone has suggested that the brass may be at fault, I aquired it with the rifle but do not know its history
Any ideas??
 
I have a 243 AI which I bought from another Forum member. I used brand new Lapua brass when I started reloading it. I also used RWS factory ammo so that I could go out and shoot straight away with it. I subsequently did some reloading with the RWS brass.

The rifle came with a Redding neck sizer bushing die, so initially, all I could with the brass was neck size it. I have since got a Hornady custom die made from twice fired Lapua brass and can now full length resize the brass.

I suggest you get some brand new Lapua brass and also try and establish whether or not the dies you have match the chamber that you have.

Good luck. JCS
 
I have a 243 AI which I bought from another Forum member. I used brand new Lapua brass when I started reloading it. I also used RWS factory ammo so that I could go out and shoot straight away with it. I subsequently did some reloading with the RWS brass.

The rifle came with a Redding neck sizer bushing die, so initially, all I could with the brass was neck size it. I have since got a Hornady custom die made from twice fired Lapua brass and can now full length resize the brass.

I suggest you get some brand new Lapua brass and also try and establish whether or not the dies you have match the chamber that you have.

Good luck. JCS

You dont say but did you have similar problems

steve
 
dies

I have only neck sized the cases that came with it and were 'supposed' to have been fired in the rifle using redding dies supplied by spud

steve
 
I cant seem to get consistance in the ammo pressure wise, the accuracy is fine but!
i have done the load development and thought i had it sorted at 44gr N150 behind a 70gr blitzking
I fired 20 shots today and probably 12 were fine, 8 have soot marks down the neck and onto the body,5 had small marks on the head from the ejector 2 had blown the primer out alltogether and 1 has blown the primer and had bad marks on the head from both sides of the ejector mechanism
I measure each powder charge out to within less than a 10th of a grain
Someone has suggested that the brass may be at fault, I aquired it with the rifle but do not know its history
Any ideas??

for starters what powder was the rifle using before you aquired it ??
 
for starters what powder was the rifle using before you aquired it ??

The guy i got it from was using 46gr of N150 behind the 70gr blitzking but admitted it was a hot load also of the 200+ cases that came with the rifle i threw away nearly half due to pressure signs mainly expanded primer pockets
just for info the load i am using is listed on at least 3 seperate sites and during load development showed no adverse signs!! first time i fire more than 3 shots ? go figure
 
The guy i got it from was using 46gr of N150 behind the 70gr blitzking but admitted it was a hot load also of the 200+ cases that came with the rifle i threw away nearly half due to pressure signs mainly expanded primer pockets
just for info the load i am using is listed on at least 3 seperate sites and during load development showed no adverse signs!! first time i fire more than 3 shots ? go figure
Ok,I thought you were going to say Varget as i had problems with carbon build up in the throat which caused pressure,I have used 150 and also got problem which scrapped my brass,if i was you I would binn the brass and buy new,firr form using a stout std 243 charge using either Vit 140/160 or H414,I have used all types of powders in a 243 AI for over 10 years and 3 barrels,so i have done a bit of testing.
also check the neck dia of your chambering to make sure you not on a tight neck,this should be stamped on the barrel,
give the gun a really good clean to make sure theres nothing built up in the throat,if you have access to a bore scope this will help.
 
Have the cases been trimmed? Have you checked neck thickness with regard to the chamber dimensions? A chamber cast would be enlightening.~Muir
 
Ok,I thought you were going to say Varget as i had problems with carbon build up in the throat which caused pressure,I have used 150 and also got problem which scrapped my brass,if i was you I would binn the brass and buy new,firr form using a stout std 243 charge using either Vit 140/160 or H414,I have used all types of powders in a 243 AI for over 10 years and 3 barrels,so i have done a bit of testing.
also check the neck dia of your chambering to make sure you not on a tight neck,this should be stamped on the barrel,
give the gun a really good clean to make sure theres nothing built up in the throat,if you have access to a bore scope this will help.
I had noticed a lot of carbon build up between the muzzle and silencer so that may be something worth a look , just a thought the load i am using is below the max for a 243 would you fireform with the same load?
 
Have the cases been trimmed? Have you checked neck thickness with regard to the chamber dimensions? A chamber cast would be enlightening.~Muir
All the cases were trimmed to length admittedly using a standard 243 trimmer, sorry as to neck thickness ,chamber dimensions , chamber cast no idea
 
I had noticed a lot of carbon build up between the muzzle and silencer so that may be something worth a look , just a thought the load i am using is below the max for a 243 would you fireform with the same load?
before you do anything mate make sure there is no carbon build up in the throat,as I said Ive had this problem and scrapped a load of brass.I only found the problem by accident whilst giving the barrel a really good clean out,I had a perfect ring of carbon break out the throat and come out on a patch,once I had made sure the rifle was carbon free I never had another problem,you think the rifle is clean but without scoping it you will be surprized what these wonder cleaners DONT fetch out.
buy new brass,make sure your clean and change the powder.foreform on a good stout std 243 load you dont have to go to the max,just make sure your bullet is seated either on or just kissing the lands,this way you shouldnt pull the bullet out of the case leaving your chamber full of powder if you have to unload,the other way is to fireform without a bullet using cream of what method but i found you dont get the same effect as using a bullet
if your struggling bring ir down to mine your not far away,we can at least load and test fire it in my workshop
 
before you do anything mate make sure there is no carbon build up in the throat,as I said Ive had this problem and scrapped a load of brass.I only found the problem by accident whilst giving the barrel a really good clean out,I had a perfect ring of carbon break out the throat and come out on a patch,once I had made sure the rifle was carbon free I never had another problem,you think the rifle is clean but without scoping it you will be surprized what these wonder cleaners DONT fetch out.
buy new brass,make sure your clean and change the powder.foreform on a good stout std 243 load you dont have to go to the max,just make sure your bullet is seated either on or just kissing the lands,this way you shouldnt pull the bullet out of the case leaving your chamber full of powder if you have to unload,the other way is to fireform without a bullet using cream of what method but i found you dont get the same effect as using a bullet
if your struggling bring ir down to mine your not far away,we can at least load and test fire it in my workshop
OK good clean to start with, already on the new brass thanks to spud, do you find the n140 has less carbon build up than n150 ,or should i bin the vit and go to hogdon
thanks for the offer of the help, i may take you up on that if the initial options dont work

steve
 
OK good clean to start with, already on the new brass thanks to spud, do you find the n140 has less carbon build up than n150 ,or should i bin the vit and go to hogdon
thanks for the offer of the help, i may take you up on that if the initial options dont work

steve
Iamm using Vit 140 at the moment its really clean,Im have put 30 shots down the tube and cleaned it,there was no powder residue at all come out or even copper,thats with a 74gr hand made bullet.with 160 you get a bit more speed but it does leave residue in the barrel.
I will be changing over to H414 as soon as thew vit 140 has ran out because it produces good velocity with little pressure signs,
with the AI it dosnt show pressure signs well untill its too late.
 
Iamm using Vit 140 at the moment its really clean,Im have put 30 shots down the tube and cleaned it,there was no powder residue at all come out or even copper,thats with a 74gr hand made bullet.with 160 you get a bit more speed but it does leave residue in the barrel.
I will be changing over to H414 as soon as thew vit 140 has ran out because it produces good velocity with little pressure signs,
with the AI it dosnt show pressure signs well untill its too late.
have you used H380 in the 243AI i have a tub of that on the shelf
 
All the cases were trimmed to length admittedly using a standard 243 trimmer, sorry as to neck thickness ,chamber dimensions , chamber cast no idea

Well. When you get erratic pressures from what was a custom rifle, it's a good idea to see if someone ordered it with a tight neck. As a quick check, take one of the cases that flattened the primers and see how easily a 6mm bullet can be seated into the case mouth. If it's tight, you may have found a problem.~Muir
 
Well. When you get erratic pressures from what was a custom rifle, it's a good idea to see if someone ordered it with a tight neck. As a quick check, take one of the cases that flattened the primers and see how easily a 6mm bullet can be seated into the case mouth. If it's tight, you may have found a problem.~Muir

in the UK any chamber which isnt standard SAMMI spec IE tight neck is stamped onto the barrel at the proof house
 
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