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Do I have a HOT batch of RL7 powder

Posted: Sun Nov 20, 2011 5:51 pm
by futuretrades
I am having problems with RL7 powder with my Cooper Mdl 21 Phoenix, chambered in 20Var Targ. Here's the deal, brass is 221 fireball, run thru a 20VT Redding FL die, to form my cases. All primer pockets are uniformed and all flash holes are uniformed. Necks have been turned to clean up between 30 and 50%. Case length measure between 1.388 and 1.394 All brass has been annealed.
Bullet is a 32gr V-max, and primers are Winchester small rifle. Powder is RL7 @ 17.5gr. I checked the chamber for seating depth @ 1.480 to the lands with a Hornady OAL guage and a 20VT modified case using 32gr Vmax. I have also double checked the chamber with a Sinclair OAL guage and same bullet, with the same measurements. I double checked and even triple checked the settings of my dies, and have gone so far as to replace my Lee press with a Redding Boss, (but that's another story). I have been seating my bullets at any wheres between .010 jammed into the lands to .020 off the lands with the same results. Cooper had me send the rifle back to make sure problem is not with the rifle
The problem I keep having, and only with RL7, is that I get a very HARD, primary extraction :wall: It does not matter where I seat the bullet. I called Cooper for their test load, which they gladly gave me. Their load is 32gr Vmax w/18.3gr H335, WSR primer, and bullet seated at around 1.859 to tip of bullet. I duplicated their load with absolutely no problems. I even tried their load with the bullet jammed .015 into the lands, with no problems. Today I loaded 17.8 gr. RE10x with bullet depth at 1.480, with comparator,to just touch the lands, no problems.
The only thing I can think of is that my can of RL7 powder is a very hot batch, but there are no signs of over pressure on the case. I did run some of the problem brass thru my FL die and they cycle fine, and even tried my Bump die on the problem brass, and these also cycled fine.
Any Ideas will be considered
Thanks for reading my long post.

Re: Do I have a HOT batch of RL7 powder

Posted: Sun Nov 20, 2011 6:45 pm
by Neil S.
Did you shoot any of these loads over a chronograph? If you are getting significantly higher velocity than the rest of us with the same load (17.5 grains of RL-7 pushes a 32 sierra at 3300 fps out of my 24 inch barrel), then you may have a hot batch of RL-7. It may be as simple as backing the charge down a little. Do your primers show pressure signs?

Re: Do I have a HOT batch of RL7 powder

Posted: Sun Nov 20, 2011 7:23 pm
by Hedge
I didn't see what type brass you're using. Wouldn't be Federal, would it?

Re: Do I have a HOT batch of RL7 powder

Posted: Mon Nov 21, 2011 8:02 am
by Rick in Oregon
Kevin - What you are experiencing may not be your ammunition at all.

Are you aware that Coopers have a proclivity for initial hard bolt lift due to the 60 degree bolt lift/three locking lug arrangement? All of my Coopers display this trait, and if you're not aware of this inherient trait, it could indeed be mistaken for hot ammo.

Many refer to this as "sticky bolt lift" or "sticky extraction" when in fact with these rifles, it's just a trait they have due to the 3-lug bolt design with a steep cocking angle. Check this out first before you get too involved with thinking you have a hot batch of RL-7, as in my recent experience most of the RL-7 of today is much SLOWER than batches from the recent past. Just a thought. :chin:

Re: Do I have a HOT batch of RL7 powder

Posted: Mon Nov 21, 2011 11:36 am
by Fred_C_Dobbs
If you're having hard bolt lift caused by excessive pressure, your brass also should be showing evidence of smear. The reason an overpressure causes stiff bolt lift is because the high pressure causes the brass to flow into the extractor/ejector depression. This causes the fired case to bind against the bold face and resist rotation. And it should be leaving signs on the brass.

Re: Do I have a HOT batch of RL7 powder

Posted: Mon Nov 21, 2011 1:10 pm
by Rick in Oregon
Fred - He's saying that on his fired brass, there is virtually no signs of excessive pressure whatsoever, just the sticky bolt lift.

Re: Do I have a HOT batch of RL7 powder

Posted: Mon Nov 21, 2011 5:34 pm
by futuretrades
Rick in Oregon wrote:Are you aware that Coopers have a proclivity for initial hard bolt lift due to the 60 degree bolt lift/three locking lug arrangement? All of my Coopers display this trait, and if you're not aware of this inherient trait, it could indeed be mistaken for hot ammo.
That is something I noticed when I first got my rifle, and as you stated I have not run into this with any other rifle. The "sticky" that I am having, is what Cooper said was a "primary" hard bolt lift, in other words the bolt has a normal amount of resistance when first lifted, but hits what they call the primary extraction point. This is where my problem is. In fact when trying to extract an empty case, sometimes I had to use a rubber mallet to open the bolt.
Earlier today I went ahead and picked up a new pound of RL7, just to try. It has a production date June 5 2009, shift Z, LOT #85088 My original can had NO production date on it. Just some real small #'s on the label. My guess is this is an older production lot.
I did load and shoot 5 rounds of the new powder, with the identical load and seating depth as with the first lot. I still got a sticky primary bolt lift, but seemed not as hard as with the first lot. I also picked up a pound of H4198 to give a try. H4198 is right at the same burn rate as the RL7. I loaded 5 rounds with it, 17.5 grains and bullet seat to just kiss the lands. I had no problems with these loads whatsoever :huh: I was thinking the burn rate might be the problem, as all other powders I tried were slower burn powders. I just guess my Cooper does not like RL7. I am going to try lowering the charge and see what happens. Thanks for the replies

Re: Do I have a HOT batch of RL7 powder

Posted: Thu Dec 01, 2011 12:49 pm
by futuretrades
[quote="futuretrades"] I had no problems with these loads whatsoever :huh: I was thinking the burn rate might be the problem, as all other powders I tried were slower burn powders. I just guess my Cooper does not like RL7. I am going to try lowering the charge and see what happens.

I did load some RL7, and reduced the load by 1/2 grain, with an OAL with comparator 1.480. This OAL just touches the lands, same as I was loading previously. Finally got some decent weather here. With this load, I had NO extraction problems. When we get a couple days of better weather, I will be shooting a few of my loads over my chrono.
I am in the process of fire-forming my brass, but because of the problems I've had, finding a load for this, I have had to either full length size or use my bump die on most of my brass. At least now, I do have a load w/H4198 to form a few of my cases, and fire-form the rest on Skippy! :mrgreen: