RL-22 The Slow Burn

[Festus]

I've been working with the Hornady 162 Amax & RL-22. The Hornady Manual lists 62.9 gr. as max and yielding 3,000 fps. I used 61 gr. as a starting load in W-W brass sparked with a F215 primer. Pressure was mild and so was velocity (2488 fps) from my 24" bbl. I worked up to 64 gr. in one gr. increments and achieved 2639 fps, still no pressure signs. My next range session took it up to 67.5 gr., still no pressure signs and velocity was just 2772 fps.

I had previously worked with AA-Magpro with this same brass and primer and bullet. A charge of 76 gr. yielded 3052 fps, which seemed to be about maximum in this rifle.

Is this lot of RL-22 a super slow burning lot? Obviously when I start with a new lot I'll have to cut the charge way back. Scratching my head here.

Festus

 

[Festus]

Sorry, forgot to mention it's a 7mm Rem Mag.

Festus

 

[loaders_loft]

I've read on this forum and others that the federal primers are somewhat mild to begin with. So, maybe you're not getting sufficient ignition? Try a hotter primer like winchester WLRM?

Besides that, try re-calibrating your scale. Maybe you're not throwing what you expected?

Others may have more insight...

 

[Festus]

Thanks, LL,

But all charges are weighed so I think I need to look beyond a primer switch to account for a 500 fps velocity deficit. Double base powders are not typically difficult to ignite but I admit to being baffled.

Festus

 

[BountyHunter]

RL22 is well known for lot to lot variance. Sometimes to the extreme. They had a major recall a couple years ago on one lot because of that.

That is why I never use RL22. Ends up constant load development unless you buy a bunch of the same lot. Just too many other good powders out there that do not have that extreme variance.

At least that is my experience based on many problems with RL22.

BH

 

[Delta Hunter]

Are you sure you're getting good chronograph readings? Did you shoot a known load through it to verify? Also, did you mic. and/or weigh the bullets to make sure they're what they're supposed to be. Just trying to throw some things out there for ya'.

I know there have been reports of RL22 varying from lot to lot, but I don't think I've heard of a situation quite like yours.

A few years ago I bought a couple pounds of the recalled lot, the lot that was way too hot. A call to Alliant got me two replacement canisters, quickly I might add, so I was satisfied.

Over the years RL22 has served me well. If you go to the websites of various 1000 yard benchrest clubs (Iowa, N. Carolina, etc..) and review their match results, you'll probably find that RL22 and RL25 account for the vast majority of winners. I accumulated some data a couple of years ago on this and that was my findings.

Anyway, hope you get it figured out. Try giving Alliant a call.

 

[Festus]

Thanks for the insight guys. I was aware of the lot to lot variation reputation that RL-22 has but I've never had results like this. My chronograph is fine but I have not measured the bullets. I doubt that is the trouble though because bullets from the same box produced expected velocities with AA-Magpro. I'll see what I can learn from Alliant.

Festus

 

[Delta Hunter]

Keep us informed. I'd be interested in knowing what Alliant says.

 

[OKIE2]

If R-L 22 powder has a variation reputation it has never caused me a problem from lot to lot this is the only powder I use in my 264 mag and 7mm mag both are the most accurate loads I have

 

[Shortmagman]

I have owned a Ruger Mark II in 7mm Rem Mag. for over 10 years and during that time I have learned quite a bit about loading the 7mm Rem Mag.

If you look at a number of reloading Manuals you will find a great deal of variation between what is given as a max load with the same powder. I know that each manual uses a different barrel and there are reasons for some variation, but it is greater for the 7mm Rem Mag. than almost any other caliber that I have loaded.

My gun has a long throat and it usually takes more powder to produce the velocity that I am looking for. I know that RL-22 has a reputation for variations from lot to lot so when I use it for loads in my gun I get some of the same things that you are getting--much lower velocity than your expected and much lower than the manuals say you should get.

Just recently I worked up a potential elk load using 160 Nosler Accubond bullets and RL-22. With the max load listed with a 160 Nosler Accubond bullet I was getting only 2700+ ft/sec velocity. So I worked up a load(1.0 grains and then .5 grains at a time) that produced 2900+ ft/sec. without pressue signs. I stopped without trying for the magic 3000 ft/sec which I think I should have gotten.

It took 68.5 grains of RL-22 to get 2900 ft/sec.. I know that this is way over the max and it can make you nervious, however that is what it took. I do not have pressure signs at all. IT IS A SAFE LOAD FOR MY GUN! I just checked the Alliant web site and they give a load of 65.0 grains for a 160 grains Speer bullet. They show 2976 ft/sec with this load.

If your gun has a long throat you could be experiencing the same thing that I am.