Slow Model 700 7mm Rem Mag?

[PrecisionRx]

Assuming the components are sound, and since both the 4350 and h1000 were slow, Im going with a shot out barrel. I have an older m70 winchester thats notoriously slow. It is about gone. I have a fresh tikka that routinely prints 70 to 100 fps slower than a 1980 built m700. Some of it is just the barrel, some could be the throat is getting highly eroded and you're loosing pressure as a result.
I also have an old article by Finn Aagard where his particular rifle took 3 grains more powder to match the stated velocities. He also had a few thousand rounds down the barrel.
I would either step on the loads to see if velocity comes up without pressure, or chalk it up to a bad barrel and move on.

Agree with Salmonhead. The best way to test this is to chono the reloaded ammo in another rifle. Velocity is pressure related and pressure depends on the length of time the bullet stays in the barrel.

 

[VICOMB]

Every 7mag is not the same.I did a test on four 7mags I had using 66.0grs of Winchester WXR(same powder as Reloader 22,just different lot),Remington case,WLRM primer,160gr Accubond.First rifle was a Ruger 1-V with a 24" barrel.It clocked right at 2900fps.Second rifle was a Remington 700 Sendero with a 26" barrel.It clocked right at 3000fps.Third rifle was a Remington 700 with a 24" Douglas barrel.It clocked right at 3050fps.The fourth rifle was a Ruger 1-B with a 26" barrel.It clocked right at 3100fps.That's quite a spread in velocity,but all four rifles grouped this load really well.Why such a big difference?Could be the way each rifle was throated and the bullet distance from the lands.Could be the actual bore size was a little different.I bought my first 7mag in 1994,a Winchester mod 70 Classic with a 26" barrel.I shot a lot of IMR4350 in that rifle.I think it's a great powder for bullets a 150grs or less,but though it will work with 160grs and heavier,I think it's better to use a slower burn rate powder for those.I like the WXR or (Reloader 22) because it works well with all bullet weights and I bought a good bit of it at $14 a pound when it was being discontinued by Winchester.A more recent powder I've used and one that works really great for all bullet weights in the 7mag is Reloader 26.The sad thing about Reloader 26 is finding it and good luck,if and when it becomes available because there are a lot of people wanting it.One thing I might add is,the modern book data for the 7mag is loaded at usually around 58-59k pressure.I think this is quite conservative for a magnum cartridge.My loads are usually about a grain or two higher,depending on the powder,than a 58-59k max book load.I'm not suggesting anyone do it,but I'm not afraid to load a little higher than that.

I just bought a 7mm rem and some Reloder 26. Plan on using 162gr eldx or Berger 168 vld. Any advice on how many grs. Of RL 26? Thanks!

 

[Deleted member 8840]

When I compared the volume of Winchester and Remington 7mag cases I have filling each case completely full with ball powder and weighing the powder after that.The Remington case held about two grains more.I found just the opposite with 30-06 cases,the Winchester held more.

It may be the belted mag case that makes the difference but not sure I've only seen it in my 264 win mag.

 

[baldhunter]

@VICOMB This is my test load with a 160gr Accubond.I think I could have gone a grain higher,but I was happy with the results.It was just under 3100fps out of my Remington 700 Stainless Steel Long Range.

 

[model 700]

Trying to help a friend, he recently shot a hand load with 60gr of IMR 4350 under a 160gr Partition with another persons chrono and was in the high 2600's for velocity, I thought that the chrono he used was faulty so today we loaded the same load, all reloading techniques were solid and chronoed them using my V3 and all were between 2675 and 2715. He also shot some with H1000 up to pressure and only got to 2800. Not sure what to think, any help is greatly appreciated.

I've had my 700-7mag for 12 years or so now and absolutely love this gun, it's one of my better shooters. My hand loads are a little smaller, I'm shooting 139 gr interlock and say's with both IMR4350 for interlocks and H1000 sat I guess the 7mag just likes these power's better. All I'm shooting so far are deer and pigs and trust me it's more than sufficient one shot and it doesn't get up. Pushing 2960 to around 3050. I don't know what your friend hunts but if he hunts like me the 139 greens are more than enough and a whole lot easier to shoot then the 160s I don't think he'll be disappointed. Just a thought. Good luck.

 

[Bowfishn]

Trying to help a friend, he recently shot a hand load with 60gr of IMR 4350 under a 160gr Partition with another persons chrono and was in the high 2600's for velocity, I thought that the chrono he used was faulty so today we loaded the same load, all reloading techniques were solid and chronoed them using my V3 and all were between 2675 and 2715. He also shot some with H1000 up to pressure and only got to 2800. Not sure what to think, any help is greatly appreciated.

When you say he also shot some with H1000 up to pressure do you have the grains of powder he used ?

 

[baldhunter]

I just bought a 7mm rem and some Reloder 26. Plan on using 162gr eldx or Berger 168 vld. Any advice on how many grs. Of RL 26? Thanks!

Reloader 26 works great with 150gr Nosler Ballistic Tips,my favorite whitetail bullet.I'm loading the 69.0gr load,went up to 70.0gr grains with no pressure signs.

 

[kfreeze]

Trying to help a friend, he recently shot a hand load with 60gr of IMR 4350 under a 160gr Partition with another persons chrono and was in the high 2600's for velocity, I thought that the chrono he used was faulty so today we loaded the same load, all reloading techniques were solid and chronoed them using my V3 and all were between 2675 and 2715. He also shot some with H1000 up to pressure and only got to 2800. Not sure what to think, any help is greatly appreciated.

I like to look at how full the case is. If there is plenty of room left in the top when I see pressure, then I try a slower powder. In your case, if I had room left, I would try retumbo, n568, n570, or rl33. And I would do that only after I made sure that I didn't have a carbon ring built up that was causing me to see pressure signs early.

 

[LIK2HNT]

Sorry if this has been already said, but buy some factory ammo and check it through the chronograph. That should eliminate the rifle part of the equation.
Have you ram this lot of powder before? Sometimes lot to lot varies more than people think. I run H4831SC in my 7 WSM. My load was close to published max. When I switched lots my groups opened up. Went to 2 grains over published max to bring it back to where it was. Slowly worked the load up watching for pressure signs.

 

[74honker]

@VICOMB This is my test load with a 160gr Accubond.I think I could have gone a grain higher,but I was happy with the results.It was just under 3100fps out of my Remington 700 Stainless Steel Long Range.

Those long range models are hammers. Love mine.

 

[kfreeze]

Quick loads shows with a plus or minus 10 % powder lot variation with 60 gr of 4350 and a 160 Nosler Partition a max of 2952 fps and min of 2707 fps out of a 24" barrel. There are other factors as well, Case volume, seating length, low barrel friction, etc. etc. you may just have a slow batch of IMR 4350.

I've seen 10% variations between my max and other people's max several times. Even when we had very similar chambers and the same barrels. The lot of n570 that I am running now starts to show me pressure signs at 79.0 grns and everyone else like to run 83 or higher grns. The speed is there for me and the accuracy so I'm happy. That's also why I don't buy powder less than 5 lbs at a time from the same lot #. Haha. The lot to lot variation can get you sometimes.

 

[kfreeze]

I bought a bunch of H1000 from a guy on here and one was opened and about half gone. I started using that powder and only got 2950fps with a 162gr ELDX out of a 20" barrel. When that powder was gone I opened a fresh batch of H1000, same load, and now get 3070fps. I thought that it was because of a primer change but ends up that the old H1000 was the culprit. Hope you figure it out.

Did you look at the lot #'s on both? H1000 is known to see lot to lot variation.

 

[jbur13]

Did you look at the lot #'s on both? H1000 is known to see lot to lot variation.

Yes, different lot #'s.

 

[tribb]

In addition to all the great suggestions listed here , I would pull the bullets off any completed rounds that may be left and weigh the charges on another scale to verify you actually are throwing the charge you want.

Uep