Please see

http://www.barnesbullets.com/information/load-data/284/

I focused on the 160 gr data.

Why is the 7mm Rem loaded so much slower than the 7mm Weatherby? I understand the powder capacity is close.

Also the 7mm SAUM has faster speeds than the 7mm WSM and both fatser than the 7mm Rem.

Some powders are the same, others not. Barrel lengths are all 24".

Does this mainly boil down to differences in pressure?

I want to confirm my 7mm Rem loads (160 gr TSX @ 3000 fps) are safe.

Thanks for any insight.

David

7mm Remington Magnum SAAMI MAP = 61000 PSI.

7mm Weatherby Magnum SAAMI MAP = 65000 PSI.

Weatherby rifles usually have significant freebore.

I don't think the loading data tells any lies. I imagine 3000 fps with 160s is attainable in the Remington, but probably not within the max pressure standard.
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"Serious rifles have two barrels, everything else just burns gunpowder."

I would STAY AWAY from the above cartridges.Barrel life is a DISSAPEARING ACT.You will need to have a drink after a shooting session.

quote:

Originally posted by shootaway:
I would STAY AWAY from the above cartridges.Barrel life is a DISSAPEARING ACT.You will need to have a drink after a shooting session.

In 70 rounds no less! Geez, what a moron.
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"Serious rifles have two barrels, everything else just burns gunpowder."

YOU are the MORON.

Nothing wrong with a 7mm RM. I have no problem getting 3000 from a 160 or 2925 from a 175 Partition. The companies that list slower loads are afraid of different chamber sizes of then new loading that are still out there from the 1960's when it was first introduced. Slow powders are the key to this fine cart. My favorite with the heavy weights above is Retumbo

I love these bullets but have been a little curious about some of the Barnes load data for certain calibers.

You don't list the specific load you are using, but I would certainly think you can get 3000fps with a 160 gr TSX from a 7mm Rem Mag. That sure doesn't match the load data you linked to, however.

Would you list the load you are using?

LWD

Thanks for the replies.

LWD - My load is 69.5 gr RL 25, Hornady brass, Fed magnum rifle primers, and 160 gr TSX.

It chronos at right around 3000 fps.

The rifle is a custom Win M70 built off a "classic" CRF action.

This load is extremely accurate in my rifle.

The load is within the realm (powder wt wise) of what I see in other manuals, but they do not use the all copper TSXs.

David

I'm guessing that's an okay load. Alliant's website shows a max load of 70 gr of RL25 for a 160 gr Swift A Frame Data and that's a pretty hard bullet. While the TSX will be longer the relief grooves remove a lot of bearing surface.

On the other hand, Alliant lists a 68 gr max of RL 25 for the 160 gr Partition. Data That strikes me as odd since A-Frames are very hard bullets with thick jackets. I would have guessed the A Frame would have had a lighter load. I'm not with my loading manuals right now so I can't see what the Nosler and Swift manuals list.

Are you getting any pressures signs?

LWD

LWD,
Again, thanks for the input. No pressure signs.
When developing loads I also went a grain higher and did not observe any signs then either. I shot in about 80 degree weather also.

I also tested 160 gr Accubonds. As I stepped through different loads, it took one additional grain of RL 25 to achieve the same velocity as that for the TSX. No pressure signs observed.

David

The Barnes No. 3 manual doesn't list RL25 for the 160 grain bullet, but it does list it for the XLC coated X bullet with a max of 70.5 grains. The data aren't interchangeable, but I would think that's a good indication that you are probably in safe territory since the TSX decision achieves pressure reductions and you are 1.5 grains under the max for the XLC.

How does it shoot?

LWD

A=-frames might be a bit harder but they are also short and stubby for wt compared to alot of other bullets of the same wt....thus the bearing area is shorter.

LWD,
Thanks again. This load shoots exceptionally well at 100 yds (< 0.5 inch 3 shot groups - I only did two of these consecutively).

I'll probably stick with the load. I am curious about the polymer tipped TSXs when they come out.

David

I just ran your load data in Quickload. Assuming a 24" barrel, the Quickload predicts a velocity very close to what you stated and the calculated peak pressure is just over 64K. This is slightly over the SAAMI (61000) and CIP (62366) max pressure ratings.

Thanks David,
That is helpful. It is a 24" barrel.

David

Kraky- good point re the length of the bullet.

This gets to the question of whether load data is a recipe or a guide. If you view it as a recipe, which I have been typically inclined to do, then this is not a good load. On the other hand, if you view load data as a guide and are a careful handloader, then this is a good load given the other factors.

While the calculated pressure for this load exceeds the spec, it is less than 65,000 psi, which is the max for some cartidges, e.g., the 7mm Wby. Thus, if you are using a modern firearm that can handle cartridges with a 65,000 psi pressure then you should be fine from a pressure standpoint. I've heard that pressure signs sometimes don't manifest themselves until well in excess of max pressure, but since you have an idea of the pressure generated, that's probably not a concern.

LWD

quote:

Originally posted by LWD:
While the calculated pressure for this load exceeds the spec, it is less than 65,000 psi, which is the max for some cartidges, e.g., the 7mm Wby. Thus, if you are using a modern firearm that can handle cartridges with a 65,000 psi pressure then you should be fine from a pressure standpoint. I've heard that pressure signs sometimes don't manifest themselves until well in excess of max pressure, but since you have an idea of the pressure generated, that's probably not a concern.

Not what I would want to do. Every new 7mm Remington Magnum ever built is a "modern" firearm. The cartridge manufacturers don't load it to 65000 PSI and the gunmakers don't build or prove them for it. SAAMI max average pressure exists for a reason.

DKim, as to your original question, why don't you call Barnes, ask for the Tech guy and ask him? After all, it's their bullet. I'll bet you'll find that they listed the max load for that bullet where they did because they ran into pressure problems with it at heavier charges.
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"Serious rifles have two barrels, everything else just burns gunpowder."

quote:

In 70 rounds no less! animal Geez, what a moron. rotflmo dancing