Hard bolt cam-over with PPU .243 ammo?

SVTCobra306 · May 2, 2013, 10:32 PM

I have a Savage Model 11 Hunter in .243, I am noticing that with factory Privi Partizan Ammunition (100 gr SP) the bolt cams over fairly hard.. not to the point that I feel it is sizing the case, but it's significantly harder than any other ammo I've used in it, including Winchester Super X, Remington, and a dozen or so of my own handloads. Has anyone else experienced this? There are minor marks from extraction on the case, but no rifling marks on the bullet or major scratches anywhere. They seem to extract fine. I'm probably just going to shoot them and reload, but I wondered if this was a common problem.

I should note that I have not noticed this problem with their ammo in my Savage Model 10 22-250...

Tomorrow I'll mic them and some new Winchester brass I have to see if I find any differences.

PVL · May 2, 2013, 10:50 PM

I have a Ruger American in .308 that cams over hard as you mention when I shoot milsurp FMJ rounds - but it chambers Rem/Win factory hunting loads just fine.

My BLR in .308 chambers the milsurp stuff with no problem.

My guess is that some guns are a little tighter in the neck/shoulder area of the chamber than others - but that's just a guess.

My concern is that if the hard cam-over comes from the chambers neck area being short, that may cause a high pressure condition. I suppose that if the primers look OK after firing, then there's no harm being done other than the inconvenience of the hard cam-over.

garryc · May 3, 2013, 08:56 AM

Some calipers would probably solve that question. Take a round that does chamber fine and one that binds. Measure from the base to the datum live at the base of the shoulder, then to the base of the neck. Then measure the oal of the case and the diameter of the neck while loaded. Measure the diameter of the case at the datum line at the base of the shoulder, bet you find the one that binds is different in the shoulder area.

I had a 243 that did that with reloads. I actually had to take the die and stone off a few thousandths from the base so it would reload. Dang fine shooting rifle though, just tight chambered

RC20 · May 3, 2013, 11:34 AM

We have seen the same thing with HXP Greek military ammo in some guns.

Subtle difference there. Not sure how it does. Re-size has not worked to correct even with a more aggressive cam over. I could do the same thing and remove a bit of material but you have to be very precise and not sure its worth it

I just shoot the civilian brass the others like in them and keep the Mil Brass for the mil guns)

I doubt you could see it with a calipers as the edges are not that sharp and you can easily see a thousandth or two difference and the whole range of head spacing is only a few thousandths (amazing they can get it that close.

Doing a trail load is more definitive and is the rubber meeting the road.

garryc · May 3, 2013, 10:04 PM

Well, you could soot a case and see where it binds, maybe

RKG · May 5, 2013, 04:41 PM

Savages are known for short leades (a plus), and the 100-gr. RN .243 slug has a very shallow ogive. I suspect your slugs may be engraving as you close the bolt. See if a 100-gr. spitzer does the same thing.

SVTCobra306 · May 5, 2013, 10:05 PM

They do not. It is not putting rifling marks in the bullet ogive, it is not really leaving marks at all. I haven't had a free moment yet to mic them but it looks like there is a difference in the rim to the naked eye.

The Winchester and Remington rounds, as well as some of my reloads, are all 100 grain SP's as well as the PPU rounds. I don't think it's the bullet, it's something with the casing. FWIW the PPU's are from two different boxes bought at two different places/times.. one at Cabela's about a month ago, one at a gun show a couple weeks before that. Along with mic'ing them, When I get finished loading up some 22-250 stuff I have the bench set for, I am going to probably pull the bullets from a couple of the PPU rounds and run the cases through my sizing die and check the length of the casings.. then reassemble them and see what happens.

SVTCobra306 · May 8, 2013, 09:44 PM

Results are in.. and it looks like the largest difference is the PPU ammo being larger in the webbing area by about .005. A trip through the sizing die fixed it, I'm just going to shoot them up and add them to the mixed headstamp pile.

On a side note, they're loaded with 41.1 grains of an extruded single base powder.. type unknown obviously, there is no way to know what it is.

May 2, 2013, 10:32 PM	#1
SVTCobra306 Senior Member Join Date: March 18, 2013 Posts: 434	Hard bolt cam-over with PPU .243 ammo? I have a Savage Model 11 Hunter in .243, I am noticing that with factory Privi Partizan Ammunition (100 gr SP) the bolt cams over fairly hard.. not to the point that I feel it is sizing the case, but it's significantly harder than any other ammo I've used in it, including Winchester Super X, Remington, and a dozen or so of my own handloads. Has anyone else experienced this? There are minor marks from extraction on the case, but no rifling marks on the bullet or major scratches anywhere. They seem to extract fine. I'm probably just going to shoot them and reload, but I wondered if this was a common problem. I should note that I have not noticed this problem with their ammo in my Savage Model 10 22-250... Tomorrow I'll mic them and some new Winchester brass I have to see if I find any differences.

May 2, 2013, 10:50 PM	#2
PVL Senior Member Join Date: February 20, 2013 Posts: 169	I have a Ruger American in .308 that cams over hard as you mention when I shoot milsurp FMJ rounds - but it chambers Rem/Win factory hunting loads just fine. My BLR in .308 chambers the milsurp stuff with no problem. My guess is that some guns are a little tighter in the neck/shoulder area of the chamber than others - but that's just a guess. My concern is that if the hard cam-over comes from the chambers neck area being short, that may cause a high pressure condition. I suppose that if the primers look OK after firing, then there's no harm being done other than the inconvenience of the hard cam-over.

May 3, 2013, 08:56 AM	#3
garryc Senior Member Join Date: November 12, 2005 Posts: 2,536	Some calipers would probably solve that question. Take a round that does chamber fine and one that binds. Measure from the base to the datum live at the base of the shoulder, then to the base of the neck. Then measure the oal of the case and the diameter of the neck while loaded. Measure the diameter of the case at the datum line at the base of the shoulder, bet you find the one that binds is different in the shoulder area. I had a 243 that did that with reloads. I actually had to take the die and stone off a few thousandths from the base so it would reload. Dang fine shooting rifle though, just tight chambered

May 3, 2013, 11:34 AM	#4
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	We have seen the same thing with HXP Greek military ammo in some guns. Subtle difference there. Not sure how it does. Re-size has not worked to correct even with a more aggressive cam over. I could do the same thing and remove a bit of material but you have to be very precise and not sure its worth it I just shoot the civilian brass the others like in them and keep the Mil Brass for the mil guns) I doubt you could see it with a calipers as the edges are not that sharp and you can easily see a thousandth or two difference and the whole range of head spacing is only a few thousandths (amazing they can get it that close. Doing a trail load is more definitive and is the rubber meeting the road.

May 3, 2013, 10:04 PM	#5
garryc Senior Member Join Date: November 12, 2005 Posts: 2,536	Well, you could soot a case and see where it binds, maybe

May 5, 2013, 04:41 PM	#6
RKG Senior Member Join Date: June 18, 2009 Location: Boston Posts: 562	Savages are known for short leades (a plus), and the 100-gr. RN .243 slug has a very shallow ogive. I suspect your slugs may be engraving as you close the bolt. See if a 100-gr. spitzer does the same thing.

May 5, 2013, 10:05 PM	#7
SVTCobra306 Senior Member Join Date: March 18, 2013 Posts: 434	They do not. It is not putting rifling marks in the bullet ogive, it is not really leaving marks at all. I haven't had a free moment yet to mic them but it looks like there is a difference in the rim to the naked eye. The Winchester and Remington rounds, as well as some of my reloads, are all 100 grain SP's as well as the PPU rounds. I don't think it's the bullet, it's something with the casing. FWIW the PPU's are from two different boxes bought at two different places/times.. one at Cabela's about a month ago, one at a gun show a couple weeks before that. Along with mic'ing them, When I get finished loading up some 22-250 stuff I have the bench set for, I am going to probably pull the bullets from a couple of the PPU rounds and run the cases through my sizing die and check the length of the casings.. then reassemble them and see what happens.

May 8, 2013, 09:44 PM	#8
SVTCobra306 Senior Member Join Date: March 18, 2013 Posts: 434	Results are in.. and it looks like the largest difference is the PPU ammo being larger in the webbing area by about .005. A trip through the sizing die fixed it, I'm just going to shoot them up and add them to the mixed headstamp pile. On a side note, they're loaded with 41.1 grains of an extruded single base powder.. type unknown obviously, there is no way to know what it is.