Home Forums Reloading Big Game Rifles Old versus new 130 gr. Speer HotCor's in a 7x57

Well I bought a bunch of 7MM 130 gr. Speer HotCor flat bases from someone on the Campfire and decided to relieve some boredom. 1 1/2 boxes of them are the old style in the yellow boxes and the rest are in the newer black boxes. The older version being shorter and somewhat less sleek looking were the ones I started with. I tested BLC2 and IMR 4895 under it. The BLC2 was a lot more blasty and did not provide the velocity I was looking for so I loaded 41.0 grs of 4895 and increments in .5 grains up to 45.0 grains. I was looking for 2800 fps and got 2825fps out of my 19 inch barrel with 44.0 grs. so I started there. First testing centered on water jugs. The older version would come apart and mostly end up in the second jug with a piece of core completely penetrating the third jug. The newer version from the black boxes acted like a real hunting bullet and held together blasting and splitting all three jugs and sticking in the 3/4 inch plywood backing I use to hold my targets. Did both bullets twice and the new version retained 77 grs and 68 grs of when weighed. To be fair in the old Speer manuals the 130 is considered a varmint bullet. So now for accuracy testing. My brass collection for the 7x57 is a mess. PMC, Federal, Winchester, Hornady, Sellior&Bellot and Remington. Both bullets shot as well as could be expected using the mixed brass, near an inch but not quite. I have decided to toss the S&B brass, had it since 1993 what is left of it anyway. In fact all of my brass is old maybe i should toss it all and get some Privi Partisan and see how it works. In fact my pitiful brass collection is why my 7x57 ended up on the semi retired list. Does anyone know if the Privi Partisan brass uses US dimensions for the extractor groove?

A Speer 1966 manual does state "The 130 grain bullet is an excellent varmint bullet..."

A Speer 1979 manual states "The 130 or 145 grain soft points are excellent for deer and antelope."

Back in 1969, Jack O'Connor reported 3100 fps with 50 grs IMR 4320, 53,000 psi, but did not list length of barrel. That puts it right on the rear end of a 270 Winchester with same weight bullet.

I haven't had a pound of 4320 in many years. I chose 2800 fps because I know I am not going to use this bullet past 125 yards anyway, mostly for night hog and coyote hunting. I could drop to 2600 fps and be good.

I just got some Prvi 7x57. I'm unsure of different dimensions for extractor groove, but with an unaided Mk.I eyeball they look the same as some older WW brass I have. After some quick measurements the case walls seem pretty uniform & primer pockets are deep enough & not too tight.

Flash holes are smaller than the old normal size.(.080") but a PPC uniformer (.060") fits a tad loose. Most new Hornady brass I've checked is also like this.

I had a bad experience with Hornady 7-08 brass and am hesitant to get anymore. I will order some of the Privi Partisan brass just because I would like to run newer brass! Personally I think the 7x57 is pretty easy on brass.

Good stuff. I was thinking about giving that bullet a try in mine for a light deer killer. Tough to beat Speer’s prices these days.

I use a lot of Prvi brass simply because I bought a bunch of Prvi ammo to have on hand. I anneal after every third or fourth loading, primer pockets are still tight, and the brass itself is pretty uniform by weight. As a matter of fact, I've never checked water volume, but of Hornady, Federal, and Remington, Prvi is by far the lightest. I believe Mule Deer mentioned that he uses it quite a bit as well. I'm not sure how the extractor groove measures against US-made brass, but I can tell you that the only 7x57 brass that I've ever had not fit into a standard shell holder is S&B. I don't know what's up with that brass, but the Prvi works fine. And aside from being uniform, the best thing is it's inexpensive and available.

Just my $02.

RM

Exactly why I have been dumping the S&B brass as it neck splits and now when it becomes empty.

I use PRVI 7x57 brass. It’s good stuff. Very uniform lot-to-lot weight and excellent case life. As RevMike stated, it does weigh less than Rem. or Fed. brass - considerably less than Rem. and a LOT less than Fed. An RCBS #3 shell holder works perfectly. Also, as someone else mentioned, the flash holes are very slightly smaller than those of domestic brass. As I’m in the habit of deburring the flash holes in new brass, my Sinclair deburring tool also opens the flash holes to the domestic .08 standard. I strongly doubt however, that the difference in flash holds means anything providing they are consistent.
Typically, when deburring domestic brass, I get quite a lot of shavings however I hardly get any from the PRVI. This makes me wonder if PRVI drills their flash holes rather than punching them.
As far as Speer bullets are concerned, my favorite deer bullet in my 7x57 is the 145 gr. Hot-cor. Launched at about 2770 fps, it decisively relaxes deer any where from powder burn distances out to about 300 yds. (My max self-imposed range, by the way.). The bullet creates devastating internal damage while still staying together and making two holes.

I used the 145 gr. Speer BTSP last year at about the same velocity and with the same result.

I developed all my 7x57 loads with R-P brass, so am hesitant to switch, but doing the math I can buy loaded Prvi ammo for the same price Im paying for virgin R-P brass. The PPU 139 ammo does about 1.5” in my M70. Bases on these factors I think a change in brass type is inevitable at some point.

I’ve been a fan of Remington brass for years. Still use it for my Roberts and my Whelen. However (in my neck of the woods anyways) it’s pretty well impossible to find for the 7x57 so that’s how I got onto the PRVI bandwagon.
If you make the switch I’m sure you won’t regret it.

I have heard that some lots of Privi brass may need a different shell holder but that's the only negative I've heard. I bought some Aussie brand 7x57 off a guy on another site and they're loaded with PPU brass and a 120 gr. HP monometal bullet. The call it the 120 gr. ACP Sidewinder. If the stuff shoots good I just might have to get more. It does look like good ammo. It just might be the ticket if I can draw a Kaibab tag for Mule Deer where they now require monometal bullets. They say it's part of the condor fly zone. Funny thing is I've never seen one on the few times I've hunted there.
Paul B.

Accuracy.. 40 grains of 3031....

The old and the new type are tight for accuracy out of my Featherweight and Ruger...

I have some older Privi ammo, white box with a band of red and blue on left end in which I had to modify a shell holder for these to fit. Not a hard job for a redneck with a dremel. I forgot to say that new brass works fine in my unmodified shell holder.

Awhile back a 1924 VZ24 7x57 was not showing any accuracy improvement with different bullet weights tried. Checked all the obvious culprits and no success. Loaded some 150 gr Nosler BT with the formula and voila. Since then if I get a 7x57 acting up in the accuracy department, I go the formula first.

Seek and you shall find.

I have used Remington brass for years and continue to keep a supply. My latest score.

Midway received Remington 7x57 brass this week. My bag of 100 is on its way........

Midway received Remington 7x57 brass this week. My bag of 100 is on its way........

I'll second that! I had some 150 grain Remington Cor Lokt bullets that refused to shoot in either my M.98 or M.70 Featherweight and the 98 is a shonuff true 1" rifle. I'm talking on the order of a 4" pattern being good. Seafire told me about "the load" and I thought, why not nothing else is working" and I loaded some up. Wow! they all shot into 1.5" groups and continue to do so. Don't know why but, it works!