Home Forums Reloading Big Game Rifles 7mm Remington mag slow barrel

Is it possible to have a inherently slow barrel or can it be remedied with just the right powder/bullet combination?

I had been thinking about rechambering my 7 mag to a 7-300 win mag. Is it a waste of time? I don't mind the extra work for a wildcat, I just want respectable velocity in the rifle.

I get 2800 fps from 63.1 RL 22 with a 154 Hornady interlock. My 308 with a 22" barrel with 150 BT are only about 75fps behind.

I don't know what causes this but do believe it is real. I would ditch that barrel and get a good one for either cartridge or the Mashburn. And if you wanted more the 27 Nosler.

Your load would be a light one in my rifle with a long throat. I am running 65 gr. of R22 with 160s for about 3050 fps. I would try some known or factory loads to see if it is the barrel or the chronograph. I had a slow barrel and it was due to an oversized chamber, I should of re-chambered it to verify but I just swapped out the barrel instead. Also the throats vary so much in 7RM you may have some free bore. Get or borrow a bore scope to see if it is the the chamber, throat or bore. Could be an easy fix.

Tell us a bit about your rifle.
Also, tried any other loads, powders, bullet weights? How are you vairifing the velocities?

Sorry I forgot to mention the rifle. It's a 700 adl with a 24 inch barrel. I have an older Shooting Chrony brand chronograph. I have tried other loads and can't find the records for those. The 63.1 RL 22 was my most accurate load.

I have a 7 STW in a 700 Sendero, but I want a more slender sporter weight gun for lots of walking. I have not shot or tested the STW yet. I just want to get reasonable performance and accuracy.

Pour in the powder until you hit the velocity that Alliant says you should, adjusting for any differences in barrel length, etc, or until you see traditional pressure signs, whichever occurs first.

I would try some R-26. Here is Alliant's data. I have similar results with Nosler 160 gr. AB.

7mm Rem. Magnum
Hornady 154 gr SST
Federal
3.22
24
Fed 215
Reloder 26
69.5
3,127

I had a slow 7mm back several years ago. I dropped my bullet weight down to 120gr Barnes and 120 ballistic tip. It was a deer hammer and all the speed you would want.

Another vote for RL 26. Helped my 7 mag big time

I always found it easy to get 3150-3200 with 150’s and RL22 in my 7RM. Are you getting pressure signs if you go above 2800? You didn’t really say

You want top accuracy or speed? You don't all ways get both at the same time.If it really is a slow barrel I'd drop down to a 120 nbt try slot of different loads with RL-19 & 22 then burn the barrel off it shooting it a lot. 1st maybe try another chronograph and bump your powder charge after assuring the chrono is ok. Rebarreling is the most expensive option but it isn't the only option. The slow velocity your getting will still kill every deer you can intelligently take a shot at. MB

I had a Ruger M77 7mm mag a few years ago that didn't like slow burning powder. It would blow a ball of fire out of the end of the barrel the size of a basketball with H4831. It didn't matter if you put more powder the speed still wouldn't increase. I switched to IMR 4350. It stopped breathing fire like a dragon and shot 200 fps faster.

Any documented factory load speeds I should run through my rifle and chronograph to verify accuracy? What chronographs are you guys using?

My Ruger 7 Rem Mag 24" was slow until I used the old H 870 powder, and lately RL 26 with 160 to 180 gr bullets. Did a lot of experiments with different powders and mine really woke up with those 2 powders.

https://www.alliantpowder.com/reloaders/RecipeList.aspx?gtypeid=2

If you're looking for an inexpensive chrono that works much better than the Shooting Chrony, take a look at the ProChrono Digital.

Magneto speed is very easy to use and no calibration or changes with light intensity, good price too. It seems as accurate as much more expensive chronys.

R22 should be good but R26 will usually gain 50-75 fps. I also liked shooting the 120 Barnes and it was really moving along 3400+ fps.

I posted about slow barrels on the gun writer forum so hope they offer some opinions. I would also be tempted to fire lap it and see if that did anything, but if the problem is a long throat it will make it worse.

I had no pressure signs. Never really tried to push the envelope. Since joining the Campfire I have just been trying to learn as much as possible. I am a central Pa deer hunter. We hunt thick, brushy, mountain laurel woods. Most of my shots are 100 yards or closer. The only thing I ever shot with my 7 mag was a black bear in 1997.
I'm sure people will say, why do you care about 100 to 200 fps if all my typical shots are that close. Well I'm a "rifle loony" . I expect more from my 7 mag. Hopefully I will be able to elevate my knowledge and the guns velocity. Thanks

Thanks for your input.

Thanks for the input.