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Primer problem
Posted: Sun Aug 09, 2015 3:25 pm
by shugie
I bought some HPS 190g for my Swing at 1000 yds, nice and accurate, quite a noticeable increase in recoil over the 155gr from the Bisley range office, but today I noticed that the fired case were not ejecting. They seemed to have stuck to the boltface, and on invesgation I found that the primer had become detached from the case, and there were black scorch marks on the case. I stopped using them after this happened twice, and then I noticed that one of the previous fired rounds had done the same. I returned them to the NSRA along with two unfired rounds, and they will be asking HPS to investigate.
While I'm waiting for this to happen, is there anything I should be looking at on my Swing mk 5 that might be causing this problem?
Re: Primer problem
Posted: Sun Aug 09, 2015 4:29 pm
by R.G.C
shugie wrote:I bought some HPS 190g for my Swing at 1000 yds, nice and accurate, quite a noticeable increase in recoil over the 155gr from the Bisley range office, but today I noticed that the fired case were not ejecting. They seemed to have stuck to the boltface, and on invesgation I found that the primer had become detached from the case, and there were black scorch marks on the case. I stopped using them after this happened twice, and then I noticed that one of the previous fired rounds had done the same. I returned them to the NSRA along with two unfired rounds, and they will be asking HPS to investigate.
While I'm waiting for this to happen, is there anything I should be looking at on my Swing mk 5 that might be causing this problem?
Probably the chamver throat tooshort and/or bore-groves diameters too small for the 190grs
R.G.C
Re: Primer problem
Posted: Sun Aug 09, 2015 7:48 pm
by shugie
R.G.C wrote:shugie wrote:I bought some HPS 190g for my Swing at 1000 yds, nice and accurate, quite a noticeable increase in recoil over the 155gr from the Bisley range office, but today I noticed that the fired case were not ejecting. They seemed to have stuck to the boltface, and on invesgation I found that the primer had become detached from the case, and there were black scorch marks on the case. I stopped using them after this happened twice, and then I noticed that one of the previous fired rounds had done the same. I returned them to the NSRA along with two unfired rounds, and they will be asking HPS to investigate.
While I'm waiting for this to happen, is there anything I should be looking at on my Swing mk 5 that might be causing this problem?
Probably the chamver throat tooshort and/or bore-groves diameters too small for the 190grs
R.G.C
Is there any way of measuring these dimensions? The barrel is a Border barrel, and it has dimensions stamped on it of G.308 F.300 Z.3070 but none of that means anything to me.
Re: Primer problem
Posted: Sun Aug 09, 2015 8:55 pm
by rox
shugie wrote:Is there any way of measuring these dimensions? The barrel is a Border barrel, and it has dimensions stamped on it of G.308 F.300 Z.3070 but none of that means anything to me.
Those numbers give you the bore/groove. You can measure the jump of the ammo with a Stoney Point gauge.
..
Re: Primer problem
Posted: Sun Aug 09, 2015 11:03 pm
by Trident
rox wrote:shugie wrote:Is there any way of measuring these dimensions? The barrel is a Border barrel, and it has dimensions stamped on it of G.308 F.300 Z.3070 but none of that means anything to me.
Those numbers give you the bore/groove. You can measure the jump of the ammo with a Stoney Point gauge.
..
You probably haven't got any jump - if your Swing is set up for 155gn bullets then the 190gn bullets are probably a very tight fit, causing the pressure problems. How easily did the bolt close?
Re: Primer problem
Posted: Mon Aug 10, 2015 8:49 am
by shugie
Trident wrote:rox wrote:shugie wrote:Is there any way of measuring these dimensions? The barrel is a Border barrel, and it has dimensions stamped on it of G.308 F.300 Z.3070 but none of that means anything to me.
Those numbers give you the bore/groove. You can measure the jump of the ammo with a Stoney Point gauge.
..
You probably haven't got any jump - if your Swing is set up for 155gn bullets then the 190gn bullets are probably a very tight fit, causing the pressure problems. How easily did the bolt close?
On the first forty rounds, same as usual as I recall, just on the last few it might have been a bit harder to close.