Pissed off about 7mm RM load data

G

g-manz35

CGN Regular
Rating - 100%
18   0   0
Location
NE Sask
I have found reloading in general to be fairly rewarding. It seems like there is great info out there, but recently my buddy picked up a Rem 700 SPS in 7mm RM and so I thought I would help him reload a few rounds and now I'm getting a little frustrated. I've loaded for 4 other guns and can get velocities that easily compare to factory ammo.

I had some H4831 and some 162gr Hornady BTSP. The load data in my Hornady 8th edition maxes out at under 60gr of H4831. This load is super lame and cronoed at about 2600 fps. So off to the Hodgdon site I go and find the start load at 60gr and the max at 64gr. So after loading to the max load of 64gr they cronoed at 2800 fps. Why are these loads so lame? So we ended up loading a few more to 65gr (1gr over the hottest load I could find) but haven't tried them out yet. Factory 150gr Corelokt rounds Chrono at 3000fps so I was thinking that we should be getting at least 2900 fps with 162gr pills. We are not getting any pressure signs, but I really didn't want to get a new reloader overloading rounds until he gets some experience. I am just trying to get a decent load for him to plink with and possibly hunt. He's fairly new to shooting and just wants to practice a bit.

Is it typical to over load 7mm RM to get close to factory ammo?
Should we try a different powder? I usually get good results with H4831

Advice.......... Thanks

G

UPDTAE: So here's the follow up. We ran these loads up to 65gr of H4831. We got average velocities of 2804 with 64gr and 2849 with 65gr. Also we discovered that my Alpha Chrony registers 50 fps lower than my buddies Oehler 35. So the "corrected" velocities would be 2854 with the 64gr load and 2899 with the 65gr load. We decided to stick with the 64gr load (Hodgdons Max). It has been pointed out that I am too stupid to know how to read pressure signs so take this with a grain of salt, but as far as my puny brain can tell there was no signs of excessive pressure (not even a hint) even when going slightly above max. Buddy just loaded them all up again tonight and all the brass was good. No stretched primer pockets etc..

Thanks to those who helped. George
 
Last edited:
7 Rem Mag has more variation from rifle to rifle than I've seen in other calibers. I've had 2800 with 154s and the 4350s on the slow end, and other people claim velocities that are in STW territory. My current one is a Kimber that does 3000 with 160 Accubonds and old IMR7828. Its not hot, but the barrel is 26".
 
Most of the 7mm Rem Mags I have owned would accept 67/68 grains of H4831 behind that 162 Hornady.
This generally churns up velocities in the 3000-3025 area.
The manuals are super conservative, IME, plus that Remington will have a long throat.
I would work up from where you are in ½ grain increments carefully.
Regards, Eagleye.
 
I get better than nosler's published velocity with IMR 4831 but lower with IMR 7828.

The 7828 and 160 accubonds is really accurate at 2915 fps so I'm happy with it. I was getting 3015 fps with 4831, 1 grain under nosler's max but like I said it wasn't quite as accurate.

This is in my 24" savage.
 
It always makes me nervous when the starting load in one book is the max in another. Sometimes I regret having more than one reloading manual.
 
2800 doent sound lame to me thats close to the same sd as a 200 gr 30 cal bullet which doesnt go a lot faster in my 300 wby admitadly i dont own a 7 mm but once you start getting into high sd they start to fall off pretty fast i bet a 150 gr would pretty fast if thats what you want
 
09outlander said:
It always makes me nervous when the starting load in one book is the max in another. Sometimes I regret having more than one reloading manual.
Click to expand...

Why?
I was out in the shop loading up ammo for two new to me rifles.
One isn't even here yet...........tomorrow, hopefully.
Study the info the books toss at you.
I usually run down the middle and move up a couple notches.
Don't quite have the testies to fill the cases plumb full and tap out enough
for the bullet, but I'm sure getting close.
There is enough duplicating info around to please most reloading spec's.
Go with want makes you comfortable.
Slow and steady wins the confidence.
 
Couple things I should add. The SPS has a 26" barrel and does not have a long throat. If you extend those 162s to the lands the cannalure is just out of the case neck. I have seen 175 blue box Federal ammo go 2830 over the same chrono out of a 24" barrel so I do expect to get over 2900 out of the 26" SPS.

I will let buddy read your responses and he can decide what he wants to do. I think we keep bumping up the charge by a half grain till we get to the 2900 range or the velocities flatten out a bit. as it is we gain about 30 fps with every .5 gr increase in powder. We are using Fed 215 primers which I understand are quite hard and won't flatten as easily as some others so we will be careful to watch for any sign of pressure.

Thanks
 
Who has read, the story in the Speer manual "why ballisticians get grey hair"?

Also read the comments Speer put in their 7 rem mag data section.

The 7 rem mag, is a temperamental thoroughbred, no doubt about it, prone to pressure spikes too. That's why a lot of the newer data is so backed off compared to the older copper crusher test data.
 
g-manz35 said:
Couple things I should add. The SPS has a 26" barrel and does not have a long throat. If you extend those 162s to the lands the cannalure is just out of the case neck. I have seen 175 blue box Federal ammo go 2830 over the same chrono out of a 24" barrel so I do expect to get over 2900 out of the 26" SPS.

I will let buddy read your responses and he can decide what he wants to do. I think we keep bumping up the charge by a half grain till we get to the 2900 range or the velocities flatten out a bit. as it is we gain about 30 fps with every .5 gr increase in powder. We are using Fed 215 primers which I understand are quite hard and won't flatten as easily as some others so we will be careful to watch for any sign of pressure.

Thanks
Click to expand...
Federal primers are usually quite soft from my understanding
 
I am having the same problem 64gn (max) imr 4831 with 168 gn berger vld at 2750 fps, how high can you go? I am using a husky 8000
 
Given the great variations in chamber and barrel dimensions, and variations between lots of powder, no manufacturer can accurately predict what pressure or velocity, that a given load will produce in your rifle. Therefore there will always be variations from manual to manual.
 
The 7RM has inconsistent pressure spikes for some reason. So the data is conservative.

Make sure your chrono is accurate, then work up. I had a 7RM load for one rifle that had considerably more powder than what was listed in any manual, worker up to carefully and watching the chrono.
 
BCboy said:
Federal primers are usually quite soft from my understanding
Click to expand...

I'll second that notion. Many people in the antique world use them because 150 year old springs don't hit firing pins the may they used to when they were new.

Also: I wonder what the powder weight is in a factory loaded round. I understand that you will have no idea what kind of powder it is, but if there are 64+grs. of it when the manuel has no listing for any powder above 64grs. That might be a good indicator of how conservative the manuel is.
 
Last edited:
Remember that the loading manuals are only a guide, it is not written in stone, that you will achieve what they did, or cannot better it. The gun you are shooting, has the final word on that. I've had as much as 300fps difference on a given load, using the same components as they did. I have also had 200fps difference in factory loads from what the box says they are doing, usually not in my favor.
 
You must log in or register to reply here.
Back
Top Bottom