7 mag slow speeds Rl-22

[hunter0528]

I developed my 7 mag load last year with Nosler 160 accubond. I worked up from 61 to 63 grains(book max) Rl-22 with no pressure signs. I found .5 moa accuracy at 63 grains. Today I went out with a chrono for the first time and measured 2860-2875 FPS. True book speed for this is 3050 FPS with a 26" barrel. I have a 24" barrel with 9.25 twist so I figured I should be closer to 2950 fps. Should I work up the charge higher? Can I trust the chrono? Or should I just stay at this velocity and charge with it being accurate? Thanks for the help

With grouping of .5 MOA I would not mess with success.

What type of Chrono? if it is based on the glint of the bullet it might be how the screens are reading the light.

 

[Rjrhino88]

With grouping of .5 MOA I would not mess with success.

What type of Chrono? if it is based on the glint of the bullet it might be how the screens are reading the light.

It is a prochrono so yes it is based on light. Seems to be a consensus though that those speeds seem right with 63 grains rl-22

 

[Rjrhino88]

I have also done a lot of work to the rifle to get it accurate. Replaced stock with McMillan, fully bedded action and recoil lug, timney trigger, replaced j lock with grayboe fluted firing pin assembly.

 

[MZmoose]

I'm running Hornady 7mm RM cases, Winchester WLR primers, 63gr of RL22 with a 160 Nosler AB in a Ruger American @ 2950 fps with 0.8 MOA. No pressure signs. I could increase the charge but I don't need more speed for my hunting purpose, so no need running higher pressure and shortening barrel life.

 

[6.506ai]

Mate has a 7rm running 180s with 2225. He gets 3000 with that load in norma cases. Maybe try changing your powder. You should be able to get 160gr bullets going up around 3200 3300 with the right powder

 

[JD284win]

R23 is where it's at. More temp stable too. My ruger loves it with 150gr ttsx.

 

[WYO300RUM]

I am using federal 215m primers. I am going to work up. I am also going to start a 168 Berger Vld load with H1000 and see how it shoots.

I bet that will be a great combo ! I haven't even tried H1000 in my 7 mag , I don't think. Been neglecting it . Always working on 300 rum, 6.5 prc and creed. Time to work on 7 mag and 300 win mag soon after moved. 168 Berger shoots great out of my rifle. Bought some 143 Hammers to try.

 

[ericbc7]

In general I will take a velocity hit in exchange for accuracy. If you want to explore the higher velocities I would personally have no problem with exceeding book maximums if I was careful and confident about my abilities to judge pressure signs. Do your load development with a chrono and don't set your goal on a specific velocity range- pressure signs rule.
You may not be able to reach your goals with a specific powder/primer combination so try a different powder. Your barrel should last for a good while in this caliber, so enjoy the journey to a reasonably fast, accurate load. Also be a bit sceptical of the load data you glean from the internet ... remember pressure signs rule.

 

[ronstone09]

I developed my 7 mag load last year with Nosler 160 accubond. I worked up from 61 to 63 grains(book max) Rl-22 with no pressure signs. I found .5 moa accuracy at 63 grains. Today I went out with a chrono for the first time and measured 2860-2875 FPS. True book speed for this is 3050 FPS with a 26" barrel. I have a 24" barrel with 9.25 twist so I figured I should be closer to 2950 fps. Should I work up the charge higher? Can I trust the chrono? Or should I just stay at this velocity and charge with it being accurate? Thanks for the help

Depend what you want to do with your rifle ! I have killed several moose with the 169 grain bullets and they didn't go 20 yards ! I never was over 3000 fps

 

[JD284win]

Also bear in mind. Published book loads are very conservative to keep from being sued. Almost all my rifles are above book max. Work up very carefully. I don't really even use a book now. I use the cartridge appropriate powder. Shoot one shot in .3 increments over a cronograph looking for pressure nodes. Then work seating depth to get the accuracy.

 

[ericbc7]

Jd284win has it right

 

[Lefty7mmstw]

Also bear in mind. Published book loads are very conservative to keep from being sued. Almost all my rifles are above book max. Work up very carefully. I don't really even use a book now. I use the cartridge appropriate powder. Shoot one shot in .3 increments over a cronograph looking for pressure nodes. Then work seating depth to get the accuracy.

I'd rather go bigger (cartridge) and not run higher pressure... Keeping the pressure down a bit is easier on the action and will burn the barrel out slower.
As to book data, I don't quite see why the myth persists that they dumb down the data. I've got a 7rum that is running at or below start charge and making 3K and change on a 175. I've got other rifles that are making book vel. at mid load.
You've got to work each rifle up individually but keep in mind if your rifle is consistently taking heavier charges than book you've bought a bit of a p.o.s.. It either has a loose barrel dimension or is chambered sloppy.

 

[JD284win]

I'd rather go bigger (cartridge) and not run higher pressure... Keeping the pressure down a bit is easier on the action and will burn the barrel out slower.
As to book data, I don't quite see why the myth persists that they dumb down the data. I've got a 7rum that is running at or below start charge and making 3K and change on a 175. I've got other rifles that are making book vel. at mid load.
You've got to work each rifle up individually but keep in mind if your rifle is consistently taking heavier charges than book you've bought a bit of a p.o.s.. It either has a loose barrel dimension or is chambered sloppy.

How is what I described not working up the load individually? Your not testing a load some body else established. It's actually the ultimate in load development per rifle. Nothing chambered sloppy and Brux barrels are not *** barrels. Hahaha. Each cartridge has a velocity threshold per bullet weight. All I'm doing is finding that threshold. I don't see how a load that's over book by a grain or so means a rifle is sloppy or has a junk barrel.

 

[Lefty7mmstw]

How is what I described not working up the load individually? Your not testing a load some body else established. It's actually the ultimate in load development per rifle. Nothing chambered sloppy and Brux barrels are not *** barrels. Hahaha. Each cartridge has a velocity threshold per bullet weight. All I'm doing is finding that threshold. I don't see how a load that's over book by a grain or so means a rifle is sloppy or has a junk barrel.

I don't know about that with brux... That is the barrel brand on my 7rum that acts so strange... My shilen (on my 7stw) is much better as to being near the consensus on books. Typically the remmy factory barrels are the worst as far as being loose and crappy, but I've got a couple of remmy 300 rum rifles that will show pressure signs at max charge.
As to going above book max. (you mentioned that you do), not really a good idea (it wil be obvious though if three books say one charge and another is lower). We had strain gauges on a couple of rifles (338rum and 7stw) back in the day. On my 7stw I was able to get to a 75Kpsi peak before I even saw a bit of shiner on the brass. Another load was running 67Kpsi and not even showing it was warm. I ended up settling on a load that was 8Kpsi less (58Kpsi peak on a cool barrel) and running the same speed as the 67 Kpsi load. At the time the 338rum was so new there was almost zero data so my brother in law simply worked his loads up with the gauge.