Loading 7mm Rem Mag

[jkoenig1980]

Hey im gonna start loading 7mm Rem MAG. I bought some 139gr Hornady Interlock bullets. My Hornady book is old real old. I have ALOT of H4350 powder and my book shows i can use "4350" but i think it means IMR. I know i can use this powder, I just cant find the load data. Any one got a new Hornady manual that shows this bullet and powder?

[sundog]

Try the Hodgdon web site. They have lots of load data.

[castnblast]

4350 is a bit fast for 7mm. It works, but I've get incredible results using H4831 with that exact bullet. work up your load, it will likely be under the max, approx. midway between start and max. I'd run 3 shot groups.

[jkoenig1980]

Actually i was wanting to load it down a little to preform like a 7mm08.

[ForneyRider]

Should be good to go with the H4350 for 139gr Rem. 7mm magnum light load.

I think factory 140gr for 7mm-08 is 2850-3000fps. Which should show up as a min. load for 7mm Rem. Mag for IMR4350 and medium load for H4350.

www.hodgdon.com has info for that powder/bullet grain combo.

I've been using the Interlocks and the SST. Pretty nice. I've gotten better accuracy from the Nosler equivalents, but the Hornady are cheaper.

[ocharry]

jk,, my hornady book shows 139gr bullet

H4350,,,,2700 fps---57.9 gr.,,,,,,,,2800 fps---60.1 gr.,,,,,2900fps---62.2 gr.,,,,,,this is the top load,,,,,3000fps-----64.3gr.

hope this helps,,,,loads straight from fourth edition hornady handbook

ocharry

[Clark]

The Hodgdon book says 59 gr for 140 gr partition and 61.5 gr for 130 gr.

Quickload says 66.2 gr for H4350 and 63.5 gr for IMR4350 for 61,000 psi [the SAAMI max average registered pressure]

The new load books are anemic, but the 7mm mag got it worse than most.
The 7mm Mauser can actually beat the 7mm Mag over the chrono with the Mag shooting max book loads, and the 7mm Mauser shooting max long brass life loads.

The Pacific load book, 1967, shows starting 60 gr and max 68 gr IMR4350 for 139 and 140 gr bullets.
Quickload thinks that load is starting at 51,800 psi and max at 75,600 psi.

Ackley 1962 also says start 60 gr max 68 gr.

[ginshun]

I have never personally loaded for 7mm mag, but I know the old man has had very good results with 140gr Partitions and IMR4831. He tends to run his loads relatively hot though, so I don't know if this is the ticket for light loads or not.

[delta58]

I have used IMR4831 as well for the 7mm mag.

[thekyrifleman]

I used H4831 for over 30 years, then swithched to RL 19 for a caribou hunt in N Quebec. Max load with 140 gr Nosler BT gives me virtually one hole groups and duplicate REm fact loads @ 3050fps. Try it.

[ForneyRider]

If you are looking for a soft shooter...

I loaded some 120gr Sierra Pro Hunter in 7mm Magnum.

I was attempting to use up some old powders I had on hand.

I use IMR 3031, IMR 4064, IMR 4350, RL 19, RL 22, and H-Varget.

Min. loads with the magnum powders and medium loads with the faster powders gave me ~3000fps. These are easy on the shoulder and soft enough to shoot all day.

I need to do more target shooting with these to see the accuracy. I've chronied them and they were around 3000fps.

Stretching the OAL out really helped with accuracy on my rifle. Of course, it turned it into a single shot. But I really enjoy these light loads.

[Major Dave (retired)]

Since all of you posting are 7mm RM reloaders, I need to know your experience with comparing chrono results with published data.

That is, does the 7 RM actually achieve (as measured over your chrony) the velocities shown in factory loading published data, and/or in the various handloading manuals?

Clark - in your 07-08 posting, you said, "the new load books are anemic, but the 7mm Mag got it worse than most." Could it be that earlier load books were showing velocities that were not actually being achieved, thereby the current books are now more realistic, and are truly showing the actual performance? Only chrono results, hopefully from you guys, can answer that question. What have you found out with your chrono?

Clark, again - I load 7mm Mauser, but have confined myself to one combination - 44.0 gr, IMR 4320, 139gr Hornady Interlock bullet, resulting in 2,950 fps.(COL of 3.02).

What loads are you referring to when you stated, "the 7mm Mauser can actually beat the 7mm Mag over the chrono with the Mag shooting max book loads, and the 7mm Mauser shooting max long brass life loads"? What loading manual do those loads come from?

One thing I noticed when comparing Mag to Mauser is that Mauser uses about 15 to 20 grains less powder charge to achieve almost the same velocities with the 139g bullet. One of the reasons for light recoil from the Mauser.

I concede that when you get to 160 to 175 grain bullet weights, the Mauser is not in the same league as the Mag. Mauser velocities (published, not verified by chrono) are about 2,700 for 160g, and 2,600 for 175g. Faster than a 30-30 (2200 for 170g).

Ironic, since the original (1893) load for the Mauser was a 173 g bullet. Used by Spanish army at San Juan Hill, 1898, to decimate Teddy Rooseveldt and the Rough Riders. The 173g 7x57 (.275 Rigby to the British) used effectively by "Karamojo" Bell to kill elephants (made him a rich man thru the sale of ivory on the world markets of the time).

My Texas deer hunting buddies give me odd looks when I tell them I am bringing an elephant rifle to the deer lease. More puzzled looks when I uncase "only" a 7mm Mauser!!!! Ha! Ha! Gotcha'! It does blow a thumb sized hole through a 120 lb Texas buck, broadside, in the heart/lung area.
"Git 'er done", if you ask me.

[HiBC]

I suggest:
The 4350 designation is an old military spec.The number gets used by multiple powder manufacturers(Hogdon,IMR,Accurate,for sure)
There are also old surplus batches and newly manufactured batches.Plants close,businesses are bought and sold,etc. Each time we get a little different powder.We cannot count on the data being interchangable.Loading manuals change,too.Please be careful matching appropriate data to your powder.

In cases like the 7 mag,you have a big bottle to put powder in and a small bore for the pressure to be released.That means pressure changes can occur rapidly(as opposed to a round like the .308,it is more forgiving) The term is expansion ratio.

IMR 4350 is an appropriate powder,as I recall the Nosler 150 gr likes it.

One of the best tools you can buy for loading 7mm mag is an RCBS precision mic.
To just bump your resize die off the shellholder will make ammo you can shoot,but brass life will typically be short and you will see a shiny ring develop above the belt.This is a stretch mark,and if you cut the brass,you will see it has become very thin.A few more loadings,and you get head separations.
The precision mic allows you to take a measurement of your fired brass shoulder,and adjust your dies for a precise amout (.002 is good) of shoulder setback in your rifle.
About $100 will get you a chronograph,I have a ProChrony.They are a very useful tool.

[thekyrifleman]

As I mentioned earlier, I have been shooting and reloading the 7 mag for over 40 years. First loading was 69 grains of H4831 with 140 gr Sierras. Velocity as measured with a Shooting Chrony was 3000fps. I have checked that probably a dozen times. Rem 700 BDL 24" barrel. 12ft from the muzzle. When I switched to RL 19 I managed 3050 and this duplicated Remington 140 gr factory loads, which I believe are listed as 3150 from a 26" barrel. So given the differrence in barrel length, that makes their numbers probably correct. I had(still do) a Ruger#1 in 7Mag 26" barrel(it's now a 220 Swift) that easily beat the Remington by 100fps. All in all, the mag is about the same with the lighter bullets, i.e., 140 grainers. Where it starts to shine is 160 gr and up. I also shoot the 7X57, 7-08, 284 Win, and 280. As far as deer are concerned there is no difference.

Hope this helps in the discussion.

[Major Dave (retired)]

thekyrifleman - what are your favorite loads for your 7x57? Also, what are your chrono results for those loads? Finally, what rifle(s) do you have in the 7x57 caliber?

[thekyrifleman]

Major....my favorite for the 7X57 is 50 grains of 4350 and 140 grain Sierras...2850 plus out of a custom 1908 Argetine Mauser. Bullet is set far out due the long throat to accomodate the long 175 grainers. 22" Douglas air guaged barrel, Brown glass bedded synthetic stock , Timney trigger @2 3/4# pull. Leupold 2X8 VArX III. Groups routinely run less than an inch, could be better if I wasn't getting to damn old to hold er' steady!!! Have accounted for quite a few deer and varmits with this combo. Longest kill was about 350 yds...two does back to back. In fact after that I put the 7mag in the safe for the really "big" stuff" because the Mauser is about 2# lighter! Now looking at 160 gr Nosler Accubonds and 4350..Expect to go to about 46-47 grains. Will use that for PA black bear. Interesting comments on this post about how much the loading books have in my opinion succumbed to the legal deparments. I mentioned 69 gr of H4831 in my seven mag Mod 700 with 140 gr Sierras. Shot that load for 30 years,never once had a fear of "too much" because when I started, I think Speer was suggesteing 72 gr as max!! Plus, I got as much as 10 reloads with no problems. Anyhow, hope this helps. Thanks for the dialogue.

[HiBC]

For what it is worth,almost 40 years ago,I began loading 7 Rem mag,also.My local gunshop sold H4831 for $1.60 a lb.That was ww2 surplus 4831.I had good results loading 70 gr behind a 160 gr Sierra,and I think this was similar to a 1000 yd load in Sierra's book.I recall at 71.5 I got only 4 loadings before primer pockets loosened up. (DO NOT USE THESE LOADS<THEY ARE OBSOLETE AND DANGEROUS)I was 16 without a mentor,finding my own way.
That old 4831 is gone,and all the 4831 we buy today is different.That old loading data,and the old loading data in PO Ackley,is out of date and dangeous.The powder changed.A buddy brought me some swollen brass with the primers fallen out,a 30-06.What gives? It was his dad's sporterized Mauser,and his dad had an "old reliable" load of 4895,I think.A reloader buddy duplicated the old load with modern 4895 and it became dangerous.
Use new data,offline or keep your manuals current.

[thekyrifleman]

HIBC...Thanks for the comments....Just for the record, I do review the new data, Have all the newest manuals, except Lyman, which is in the mail. I guess the point I was trying to make that didn't come across too well, is that the lawyers have gotten into the game, much like all other areas of business. One other thing, that buck a pound H-4831 is sorely missed!!!!