Home Forums Reloading Big Game Rifles Hornady 7mm 175 RN minimum impact velocity

I've (finally) run across a couple of loads for my 7x57 Mauser that were both accurate and consistent. But both worry me a little, hopefully the combined experience here can help steer me in the right direction.

Rifle is a tang safety Ruger M77, with the barrel shortened to 20". PPU/PRVI cases, CCI-200 Primers, H-4895 powder, 3.065" COAL, .1" jump to the lands.

37.5gr @ 61 degrees
AVG VEL - 2284
ES - 24
SD - 10
Will this bullet expand reliably with 1700fps impact velocity without striking bones? If so, my load development is done because I will stick with this load. Very mild mannered and 1" (+ or -) groups

39.5gr @ 61 degrees
AVG VEL - 2381
ES - 18
SD - 9

I feel like this one could be pushing the throttle too hard for H-4895. Close to 2400 fps with a relatively fast powder and short barrel. Recoil and muzzle blast are noticeably sharper, but the groups were wonderfully small and probably the most consistent (ES,SD) load that I have ever developed.

38.5gr was also consistent, but the accuracy wasn't there. So I am also thinking of trying 38.8, 39 and 39.2.

Don't know the impact velocity for sure but we've taken elk out to 500 with that bullet out of an STW and it's never given us any reason to doubt it.

Bottom line, I can't see a reason to worry about 1700 fps and it opening.

Dober

Here is what Hornady says about MUZZLE velocity on its web site about Interlock bullets:

InterLock� (RN, SP, SP-RP, FP, HP)

The aerodynamic secant ogive of the Hornady InterLock� delivers flat trajectories and great accuracy. It's tapered jacket allows for deep penetration and controlled expansion while the InterLock ring locks core and jacket together.
More about InterLock Rifle products...
More about InterLock Handgun products...

Controlled expansion with deep penetration.
Recommended muzzle velocity range: 2000 to 3300 fps

I would look at a slower burning powder than the 4895's. I would think trying W760/H414,one of the 4350s would give you much better velocity. TRemeber that the 7x57 ammo and most reloading data is drastically under what the cartridge can actually do because of those weak early 1893 and 1895 Mauser rifles. You're probably at or close to the limit with 4895 but W760/H414 (same powder, just different lots) had given me much higher velocity in my 7x57. With the 140 gr. Nosler Ballistic Tip I get 2800 FPS using W760. from a Winchester M70 Featherweight and sub-MOA accuracy. I've only started trying that 175 r. Hornady RN and 44.0 gr of W760 gave 2350 FPS from the Winchester, 2310 FPS from a Ruher #1A and 2410 FSP from a custom mauser with very tight chamber anf match grade barrel. According to the Winchester booklet that has the data, the load is supposed to give 2400 FPS at 44,500 C.U.P. I do wish they'd redo those loads in P.S.I. measurments but I'd guess that's probably close to maybe 50,000 P.S.I., give or take. Your rifle was designed to handle loads in the 60 to 65,000 P.S.I. range so you can go higher by careful loading practices. The Nosler loading manual shows loads as fast as 2574 FPS with the 175 gr. Nosler Partition. Nosler shows a max of 2470 FPS with IMR4895, FWIW. They used a rifle with a 22" barrel. My rifles, except the Mauser have 22" barrels. The Mauser is 23". Granted the 7x57 is no long range magnum round but the ammo makers sure do it a disservice by not loading it to it's full potential. Nosler also shows 2520 FPS with 45.0 gr. of IMR4350. That is the max load BTW. Even with a safe max load, recoil is quite mild from a 7x57.
Paul B.

I was gonna suggest H414 also but if I were you, I wouldn't angst over 100fps. The 7x57 has been killing a variety of stuff with that sort of load at that velocity for a long time.

Using data from an older Hornady manual, I use a charge of 40 grains of 3031....with the 175 RNs....it states MV should e about 2400 fps.. but the chronograph for both my Rugers and Model 7-, ALL with 22 inch barrels, registers 2650 fps...

my main appeal was the accuracy.. the MV was just a bonus...

on the other end, I have shot it with a load of SR 4759, thtat gave an MV of 1800 fps....

at 100 yds, it managed to penetrate thru 18+ inches of pine tree as a back stop and kept on going...so I am sure the MV at 100 yds waqs 1500 fps or less...

That is why I love a Round Nose... they will open up nicely, even at low velocity...

with the high sectional density, it will penetrate quite nicely also...

Thanks for the info all. Actually, I started with H-4831sc and had really poor luck. Groups were adequate at best. Velocity/ES/DS were all poor as well. I've had good luck with H4895 with just about everything I have tried it in, so I figured I would give it a whirl. If nothing else I've got a better load than I did with 4831sc, and bear season opens on the 1st.

I do have a pound of H4350 to try out next go around...

what do your cases look like with this one? flat primers? ejector mark? If I was getting those sorts of ballistics from mine, with that accuracy, I'd be done looking. I'm saying all this cause I need to be working with the 175 g roundnoses in my Ruger, since nothing else has worked so far.

I am working with RL19 in my son's 7x57 right now. I am actually working with the 160 PT's. I am hoping to find a load in the mid 2700's to 2800 with it. If I don't get it with RL19, I will give W760 a try, it seems to have alot of fans.

Nothing I can identify as pressure signs, what worries me about it is that I can't find any actual published data for it. The closest I have come is a 30 year old issue of Handloader that referenced 40gr and 175 Speer Magnum bullet. Second closest would be 175 Nosler Partition 7mm-08 load from Hodgdon. That shows 37.5gr as MAX with a velocity of 2354 from a 24" barrel and 2228 with a 15" barrel. So I am guessing the 37.5 grain load might be pretty close to 50,000 CUP.

Anyone want to supply a Quickload prediction?

Bullet: Hornady 175 RN
Cases: PRVI (61.3 gr of water)
Primer: CCI Large Rifle
Powder: H-4895 (37.5gr to 39.5gr)
Barrel: 20"
COAL: 3.065
Jump to lands: .1" (One tenth of an inch)