7mm Rem Mag Loading Conundrum

daman2270

daman2270

New member
So...I have a hunting buddy that shoots a 7mm Mag and he would like me to handload him some loads that were developed for him long ago by a "buddy" of his. Here is where it gets interesting. The load he wants and swears shoots amazing in his gun is 66grs of H4831 with 160gr Nosler Partion and Fed 215M, however according to my manuals this is a big overcharge, top charge in my manual (and Hodgdon site) given that bullet weight is 60grs. Now is this a case of old load data i.e. H4831 has changed it's formulae since those last cartridges were loaded? He isn't sure but thought maybe the early 90's was when he got these last ones done up, but who knows how old the powder was that was used. The loader did specify H4831 on the stuff he loaded.

So long time loaders I am interested in some guidance here. I have been loading for about 5 years now but only my own stuff from scratch. I don't want to blow this guys gun up or worse him up. My thoughts are a new load needs to be worked up just to be safe but I have zero experience with a 7mm Mag so maybe this is all possible....and I am just chicken with the thoughts of all the bad stuff that can happen shooting hot loads.
 
Well, if it was a really good friend I'd have him come over and "help" me load him some ammo.
NO WAY would I load anything that wasn't within book specs.
 
I definately wouldn't go there, that is 10% above the max load.

If he has any of the old ammo left, might be good to just pull the bullet on one and weigh the powder charge. Maybe he just is remembering wrong or wrote it down wrong the last time.
 
Wish I could pull a bullet, unfortunately he used the last of the ammo on a recent elk trip and has nothing left. I would have done something about it before I pulled my trigger on the last cartridge but.... Funny thing is I have collected all his old brass and polished it. Really other than a small amount of primer cratering here and there no real signs of excess pressure.

It is clearly written down on two boxes he used to carry his shells in, same load was also used on another 160gr Nosler Bullet they don't make anymore...clearly had it mark 66gr H4831. I guess he also had some 162gr Hornady's loaded with the same charge. Just makes me uncomfortable, I guess that really should answer my question.
 
Id definitely start over and work back up to find the max for that load/rifle, checking for accuracy along the way. No way would I throw 66 gr's in the case and roll the dice.
 
Just checked my books and Sierra load manual lists a max load of 63.6gr H4831SC with 160gr bullets using a Fed 215 primer. All of my other load books (hornady, nosler, and speer) list max charges below that of the Sierra manual.
 
Thanks for the info/feedback everyone, really is what my gut and head was telling me all along. I can't see that I have any choice really, I certainly don't want anyone to get hurt or have to live with being part of it.

It is curious how much of a difference there is between the Sierra manual and the others but I guess that is part of the black art of reloading, lol.

Thanks for the info RRA223, I will have to tell him to buy some extra powder, primers and bullets because there is going to be some work to do here. Wish his other buddy was still alive so I could get some more info as my friend doesn't have much of a clue.
 
i shoot 69.5 of H-4831 (long cut) with a 139. warm load. the H-4831 sc is a little faster , i have not shot much of it, none in the 7mmg. and i have not or chrono" d it against the long cut yet. . i have used all the mag primers : 9.5M, cci250 and WLRM and the 215 gave me HIGHER pressure and higher velocity and higher ES. BOTH HOGDON MANUALS 25 AND 26 SHOW A MAX OF 66.0 for a 162 grain bullet.
 
Let him load and you over see him. Anything ever happens you'll find
out his family comes first and you'll get sued. I don't load for friends and
I always tell people up front if they shoot my guns that they are shooting
reloads.
 
I looked up a load I have for a 160g SIERRA SPBT that was a great load 62.7 of Imr 4831 this was in 1977. Today its over max as your friends load but not by much. I now shoot 139g bullets for most of my hunting in a 7mm mag.
jim
 
If I loaded it; ONLY me, my wife, or my kids will shoot it. Even, if you are shooting my gun. I'll buy some factory ammo if need be.
If you loaded it; we won't be shooting it.

My house. My rules.
 
Originally Posted By: RONINFLAGi shoot 69.5 of H-4831 (long cut) with a 139. warm load. the H-4831 sc is a little faster , i have not shot much of it, none in the 7mmg. and i have not or chrono" d it against the long cut yet. . i have used all the mag primers : 9.5M, cci250 and WLRM and the 215 gave me HIGHER pressure and higher velocity and higher ES. BOTH HOGDON MANUALS 25 AND 26 SHOW A MAX OF 66.0 for a 162 grain bullet.

That is interesting, on their site they have a max of 60 grs for a 160 gr pill. I can see a small variance but a 10% difference between their manual and the website.....what is that.
 
Your buddy's loading data is correct, 66g of Old Military surplus 4831 with a 160 was ok back in the day.

With today's lot #of H4831, it is a little faster and 66g may be an over load.

65g of R#22 with the fed 215 is not an over load and is a great load for Rem 700's with 160's and work up to that load because lot# of powder can vary.

By the way, reloading manuals are all over the map on maximum charges. Maximum charges that they have listed are for their test barrel and the lot# of powder they are using.

When you get into reloading for a friend, it should be a very good friend indeed....or pass. You will get blamed for anything and everything.
 
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Hodgdon Manual #26 1992 had 66gr/H-4831 as max load with 160gr bullet in 7mag. Hodgdon put out a Flyer date 2010 and list max of 64gr/H-4831 with 162gr Hdy for the 7mag, Hornady has 59.7gr/H-4831 max. Even old Pet Loads had 66/65gr/H-4831 with 160gr as accurate loads for the 7mag.

I have some of that H-4831 from the early 90's and I haven't compare it to the new H-4831/H-4831sc.

Myself I would start over with the newer powders H-4831/H-4831sc if he's a friend he should understand if not don't load for him.
 
Well, I was going to say something, but it looks like roper pretty much nailed it.

I have shot 65 grs of H4831 for many years using the 160gr Speers. But read again what Roper is saying and go with that.
 
daman....have him read the above responses....
this entire situation could be a can of worms for you as well as for him....no one knows for sure what the load might have been....the loader has passed....to many variables.....powder,primer,brass,bullet seating depth....even the partition bullet has had design changes over the years....
be safe and start over with current available products and work up a load/loads.
and don't forget......there hasn't been any tort reform......
 
Any time you change any(****ANY-ANY***) component of a load you need to go to a safe starting load (10% under max published)and work up. Thats why they sell bullets in 500 rd. boxes(or get bullets in same lot) and 4 and 8 lb. cans of powder.
 
I agree.. You need to start over.. Develop a new load .. Me, I only load for myself, I don't need the liability..
 
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