Home Forums Reloading Big Game Rifles 7mm mag load data

I'm getting ready to load for my hunting bud's 7mm mag and was looking for suggestions. I've got a hundred 140gr. TTSX bullets and an 8lb bottle of IMR 4350. Don't have the rifle available to work up a load so was looking for something that has worked well for others. I appreciate any help/ideas that you can come up with.

I shoot 65.3grs of IMR-4350 in three 7mags with 139-150gr bullets.As always start lower and work up work up.Getting 3240fps with 140's and 3200 fps with 150's.

Loading for your bud is the beginning of a process that has many bad outcomes and few good ones particularly if you don't have his rifle in hand.

The term "liability" comes to mind.

You can say that again.

63.5gr with a 150 @ 3200fps? that's 4.5gr and 300 fps over max per the Hodgdon website. Too warm for me, thank you...

Before we all get all rapped around the flag pole as to what load data is safe, and what is not safe, please consider the following:

Hodgdon Manual #26 written in 1992 Lists the following:

7mm Rem Mag 139-140 Grain Bullets:

H-1000 Start 73.0 grains Max 76.0 grains

Hodgdon #27 written in 1996-97? Lists the following:

7mm Rem Mag 140 grain Nosler Partition

H-1000 start 67.0 Grains Max 70.0 grains

Now my 7mm mag load in 1997, which was worked up from the 1992 book and was 75.5 grains of H-1000 and the 140 grain Nosler Partition. My rifle did not self-disassemble when it read the new book. Hell, the max in new book was 3 grains below the minimum in the old book.

Now everybody knows you don't use data from old loading books. Because powder changes and bullets change, et al. So maybe Hodgdon changed the formula for H1000, and that's why we got the new 7mm Mag Data.

At the time 1997 I was also using a Model 70 SS 26" barrel in .300 Win Mag. My load was 76.0 grains H-1000, under a 220 grain Nosler Partition bullet. The 1992 book had 77.0 grains of H1000 as the MAX. The 1997 book 78.0 grains of H1000 as the MAX.

So H1000 between 1992 and 1997 did not change, but the 7mm Rem Mag data took a big downturn. Why??


Grain of Salt Time:

Well at one time I was a type 6 FFL holder, that means I was a licensed maker of ammunition and reloading components other than Armor Piercing ammunition. I was told by a powder industry insider that the popularity if the 7mm Mag World wide had a big influence on them downloading the data. Everybody that made rifles was chambering for the 7mm Mag. Rifles were being made in the US, South Africa, Europe wide, and Asia, with all kinds of different reamers and chamber spec's. Some 7mm Mags were very long throated, some where very short throated. I was never told why the 7mm Rem Mag had so many variations of chamber spec's, when other cartridges seem immune to the vagarities of the rifle makers. But the powder and ammo makers really downsized the loads of the 7mm Rem Mag in the Mid 1990's due to some un published and unannounced problems.

In the early 1990's when I bought my first cronograph, I clocked early 1980's made factory Remington 7mm mag ammo that broke 2993 FPS with 175 grain Bullet. By 1998, it was hard to find new load data or factory ammo that broke 2800 FPS with a 175 grain bullet.

Even today when perusing my new Barnes #4 manual the MAX velocity listed for the 7mm Mag w/175 grain ball is 2757 FPS.

Nosler #6 is more generous as it lists 2970 FPS for the 175 grain Partition with Reloader22. But my crony always said Nosler was always a tad generous with their stated velocities gotten with their published loads, But YMMV.

None of the above should give anybody the go ahead to charge up a 7mm Rem Mag to levels well above current book MAX's. In handloading prudence is always the key.

But newer shooters and reloaders must made aware that the 7mm Rem Mag has had more screwy data than just about any other round. Except maybe for all the Weatherby Rounds, which is a story for another day, but to give a hint, it also involves chamber and throat spec's.

Best of luck with your reloading,

Bob

Amen, and unless you have a license, I don't think you can do it legally.

Liability is always a problem when reloading for some else, but is NOT against the law to reload ammo for a buddy/friend/relative for free, with them supplying the components. It may not be smart to reload for another, but it is not illegal yet....

But it is against the law to reload ammo and charge a fee for that service, or to sell the reloaded/manufactured ammo, unless you have the correct FFL.

Bob

My all time favorite load in my 7 mag is as follows:

Brass - Remington
Bullet - Nosler 140 grain accubonds or ballistic tips
Primer - Federal GM Match 215
Powder - RL-19
Load - 65.5 grains
FPS - 3350

Shadow: Don't have a flagpole to get wrapped around. And we all know that loading data varies from source to source. And we all know that loading data (and particularly 7Mag data) has trended down over time.

That trend may be partially due to the fact that manufacturers now have access to pressure measuring equipment that they didn't use to have. Part of it (in the case of the 7Mag) may be due to the pressure variations with that particular cartridge that JB has educated us on.

It's still (so far) a free country. Feel free to load whatever you want.

But, as for me, I prefer to be cautious (prudent) when there are pressures in the 60,000 psi range right next to my face.

Your are assuming quite a bit. It was you that admonished the poster about his chosen 7mm Mag load. It was you who held the Hodgdon Bible up high and said "his load is x grains above max, let's beat him". Further HP White labs has been pressure testing loads for ammo companies and shooters, since the early 1960's if not before.

Listen sir, loading manuals are not stone tablets that come down from above. They are guide, nothing more or less. A load is "safe" only in the rifle it is developed and tested in. What generates 60,000 PSI in your rifle, may only develop 55K psi in mine, or 65K psi in somebody's else gun.

Is your 7mm mag chamber and throat the same as anybody's else???? That would be a no.... Are you and the poster you took to task using the same case, powder and powder lot, primer, or bullet lot #? The answer is also big fat NO.....

I have had rifles top out, and blow primers with loads 3-4 grains BELOW book max. I had a Ruger #1 in 257 Roberts 26" barrel, that used 52 grains of H-4831 and the 100 grain Nosler Partition, and developed 3250 FPS velocity. That load was so mild IN THAT RIFLE, that I could reuse the cases 8 to 10 times. Was it over the book, any book, you betcha.... But in that rifle only, was it "safe".

Have you ever owned a "wildcat" cartridge? I mean a real wild cat that has no load data existing that you could find? Well for those there is no BOOK... No max's no mins. Nada.. Well I have, and it's an adventure. But you do learn a lot about developing safe reloads. For me it was a 30-338 in 1976. I had to used 300 H&H data as a starting point, even though my case held like 7-8 grains more powder. I could not use 300 Win Mag data, or 308 Norma Mag data, because those cases held even more powder than mine. I have also "reloaded" for clients using a 350 G&H Mag, and a .338 Poacher's Pet, which was based on a 9.3x74 rimmed case. Or how about a .500 3" Boswell in a double gun or .495 A-Square, or a 460 Weatherby Short. I devloped loads for all those and more, several years BEFORE the A-Square Manual come out to cover those more exoteric rounds.

So sir, SAFE as it is defined, is not what the book says, or what I say or what you say, or what JB says. SAFE is developed by working up loads from the bottom. And what is SAFE in your rifle, and it is safe in your rifle alone; and that is not determined by any book, or manual or tarot cards.

Regards,

Bob

Easy, Bob. Let's see if we can have a civil dialog.

I haven't assumed anything.

I did not admonish anyone or say "let's beat him". (Speaking of assumptions)

Simply said it is too hot for me. My opinion...you are welcome to yours.

As to what is "Safe", yes, there are many variables, so that a given load can, and will, produce difference pressures indifferent rifles. But the only way one can know what the pressures are is to measure them with sophisticaed equipment that I don't have access to. Hence, I prefer to be conservative. Getting an extra few fps ain't worth the risk to me. If you, or others enjoy pushing the throttle down, that's your choice, and I wish you well.

Well shoot SouthTexas I thought I was being civil. Don't remember calling you stupid or thick. Was there something I said to lead you to believe that I was insulting you??? Was there something I said that lead you to believe that I enjoy pushing the throttle down while reloading, in some fruitless search for those last extree FPS???

As far as admonishing the other poster; Sure you did. You had to look on Hodgdon web site or their loading manual to determine that the said poster was x grains over maximum. You did not guess, or assume, you looked. And after you looked you "assumed" that his load was unsafe for your delicate disposition. And you could well be right, or you could be very wrong. You have no way of knowing unless you worked up to that load, in that rifle. Your only guide is what Hodgdon said. Are they right? Who knows? They may be. So should I sue them if I top out a load below their book MAX?

What I have and will argue is safe methodical reloading development. And that development does not stop when I reach X grains of Y powder, in Z case, with AA bullet, at BB velocity; just because some pilgrim who works for Hodgdon said so.

My "safe" will differ. It may be higher; it may be lower.

You savy?

Bob

Very well said, and fantastic explanation!

Yeah, I savy....you are welcome to use whatever methodical process make you happy.

As am I. And I prefer to lean on the pilgrims who have access to more data than I.

I didn't read all responses, but did a few. Liability? Yep. Not to mention the fact that your buddy gains nothing over a box of factory ammo from having you load up rounds for a gun that you don't even have to shoot and customize the rounds to.

I suggest you get your hands on the rifle, use current manual data, and work up the loads yourself, starting low. If you design an accurate load, then have him buy you more bullets and primers, if you can find any, (because that 8 lb. cannister will last a very long time),and load him up what he can pay for. Otherwise, I wouldn't fool with it.

I've been loading for the 7mag for 15yrs.As far as the magnum 7mm's go,It's hard to beat in terms of performance and efficiency.When the 7mag first came out,it was loaded much hotter than it is today.In fact,some of the early manuals loaded it hotter than my loads and the published velocities were very accurate for those loads.I really see no difference in IMR-4350 15yrs ago and the powder I use for it today.What I have seen,is some larger magnums have come out and when they do,they are compared to whatever is already out.The result is usually the new one is loaded hot and the older one is loaded down.Same thing happened to the 7STW.It can still achieve velocities in the 3400-3500fps range but when the 7mm Ultra Mag came out,it too was loaded down to make room for the new big boy.I slowly work up my loads and back down a grain or two when I start to see pressure signs.Reloading manuals are guides and every rifle is different so loads should always be worked up for each individual rifle.I've seen some rifles that max out with starting loads and others can be loaded much higher.As stated in one of the other post,that's how loads are developed for wildcats,by starting low and working up.

Thanks for the input baldhunter. I appreciate everyone's concern about liability but I have been reloading for close to 20 years, just not the 7mm. I am aware of the risks. Yes I would like to have the rifle to work with but he lives 700 miles away and I see 1 time a year during hunting season. I planned on taking the suggestions from here and compiling them with the information from all my recources (Nosler, Barnes, Sierra, Hornady, and Lyman's books) to come up with a safe load that has a higher chance for accuracy. I thought the personal experience/loads of some here would be good additional data to factor in my search for a good load for him. If some here feel that is irresponsible, I appreciate that as well but disagree.

Without the rifle on hand, I'd suggest that he buy some premium factory rounds, and end up with the same accuracy...

Not sure about US rules, but up here he could just box the rifle up and mail it across the country and back for under $75...