Unstable powder

Bear_Blade

Bear_Blade

Regular
EE Expired
Rating - 100%
5   0   0
Location
Alberta
So in the last year, I have been playing with Reloader 17, 210 grain Matrix bullets in my .308.

Things were going really good. Velocities around 2620, decent groups, not great but really good.

Last month I had an issue, that I was warned about... Temperature instability! Boy! was it ever!

I had worked up a load that showed no pressure signs... at all... then I took the last loaded rounds out to the range, and on the second round, blew a primer clean out of the case. Inspected the bolt, no damage, no other damage to the case, but the primer. Extraction was easy, so like a doorknob, loaded another round, same result... Hmmm, says I!

I remember reading the warnings of the powder being unstable, but wow! I also remember a couple guys recommending another powder that could give me similar velocities, but more stable. I tried searching, but couldn't sort out the search parameters. Could someone point me in the right direction?

Also any comments on RL 17?

Thanks.

Pierre
 
Last edited:
The first thing I'd ask myself was how many reloads on the cases and if I remember the primers going in a little easy. The only time I've popped primers was due to me mixing in some bad brass with my good stuff. The two primers that just dropped out were obviously due to loose pockets. How hot was the day? I'm going to assume you would know better than to leave your ammo sitting in the sun on a hot day, but I've had the odd moment, I think the vast majority of us has.

How full was the case? I'm not 100% sure about this but doesn't loading light charges of slow powder result in some unpredictable pressures? 1600 fps seems a little slow even for 210's. If your going for light loads Hogdon claims that H4895 can be loaded light and it's also an extreme powder. If you go to their web site they have instructions on how to work up light loads using H4895 and Trail Boss.

I'd give H4350 a try if your goal isn't to shoot heavies with light charges. It shows that it's just a wee bit faster on the Hornady manuals burn rate chart. Hornady are dirty liars but that's part of their marketing plan so I'd say that H4350 has pretty much the same rate as RL-17.
 
Last edited:
If extraction was easy and no other signs of excess pressure i would check for loose primer pockets as well. Haven't used R17 so i can't comment on it, use a lot of Hodgon and IMR powder and don't own a 308 thank god, so i'm not a lot of help. Try Varget.
 
So I messed up the initial post with an incorrect velocity. Blame it on fat fingers!! :)

2620 is the average velocity of 10 rounds.

I didn't use the chrono the last day I went out, just went out for a couple hours one afternoon to shoot.

I used 49.2 grains of RL17, Lapua brass, and federal primers. OAL 2.81 Charges were slightly compressed.

There were a couple of primers that seated light. But I will also comment that recoil seemed sharper.

Thanks for the responses, I apologize for the incorrect velocity, but my goal isn't reduced loads.
 
If you blew primers but have no other pressure signs and the bolt lifted normally (read easy) then I would blame it on loose primer pockets. Check your brass, if your primer pockets are loose throw them out.
 
Im running 46 grains rl17 under a 208 amax. At 46.3 I'm getting flattened primers. I realize different bullets but I'm running a longer oal. Maybe 49 is a little stiff to begin with?
 
Two friends using RL17 in there 284win quit using Rl17 as they blew primers in the hot days of summer shooting F class, it is a double base powder and will spike in heat,
for your .308 win you might like others said try Varget or Vt 150 and use the Lapua Palma brass with the small rifle primers,primer pockets will not get loose as fast as regular brass
manitou
 
I haven't found any reload data for RL17 and 210 gr powder. But I did a lot of searching, and reading, there is a lot of info on the Hide, with some guys running heavier powder charges. I know, their set up isn't mine, that is why I started at 45 grains, and worked up. I had slight flattening at 49.5 grains, and backed off. I also had a nice node at a lower charge, so may end up playing around there.

Honestly, with the fluctuations in this powder, i am likely to give up on it.

As for varget, I have that, but was advised it is to fast to push heavy bullets. Thoughts?
 
Bear_Blade said:
I haven't found any reload data for RL17 and 210 gr powder. But I did a lot of searching, and reading, there is a lot of info on the Hide, with some guys running heavier powder charges. I know, their set up isn't mine, that is why I started at 45 grains, and worked up. I had slight flattening at 49.5 grains, and backed off. I also had a nice node at a lower charge, so may end up playing around there.

Honestly, with the fluctuations in this powder, i am likely to give up on it.

As for varget, I have that, but was advised it is to fast to push heavy bullets. Thoughts?
Click to expand...

To push the heavys at a velocity that you need you have no choice but to use a double base powder. Varget is definitely too fast, I use VV N550 but once again it is a double base powder and is temp sensitive. I have not used the RL series powder so I can't compare, but I have had great luck with N550. The guys at ATRS also run N550 btw.
 
Perfect! That is the powder I was trying to remember! Thank you! Back to the bench. Gonna pick that up right now. Also just picked up a RCBS Powder Master Electronic Powder Dispenser & RCBS Powder Pro Digital Scale.

Looking forward to some new work ups!

Range report to follow.

Thanks for the help and suggestions!
 
CanuckR said:
Im running 46 grains rl17 under a 208 amax. At 46.3 I'm getting flattened primers. I realize different bullets but I'm running a longer oal. Maybe 49 is a little stiff to begin with?
Click to expand...

I agree with that..

I have the same thing. FGMM, 208 AMAX, Lapua Brass. 46.0 Gr. There was another node around 48.2 but flattened primers and high 2600's. That was pretty hot though. You're pushing a few more grains AND much more compressed. I load mine over 3" long. Different bullet, but I'm guessing you are compressing a lot more than you think.

I think the load you have is pretty hot.


I have a Chargemaster but not overly impressed. Make the modifications to speed it up, but still weigh every load. It's not the most accurate, and those that say they are, aren't overly accurate to begin with.

The Mcdonald straw helps. Google it.
 
If you use n550 I would recommend working up your load now, then come next summer take a good hot day and work up another load for the hot summer days. You will likely drop a few grains in the heat of summer.
 
Bear_Blade said:
It seems a logical solution. shell_guy's post is on the same line. Any others do something similar?
Click to expand...
You can run a single load if you develop it during the hot summer weather but in order to push the .308 with a hot load you have to have a separate load for most of the year and one for the heat of summer. Unfortunately that's just the way it is when you are trying to push a .308 to do more then it was designed for. If you want the big velocity numbers with 200+ gn bullets you should switch to a 300wm.
 
So in my effort to "get to the bottom of this" I thought I would disassemble some of the loaded rounds I had left from the range trip I mentioned earlier, and also recycle components. I did the weighing on the new digital scale. After calibrating, and checking with test weights, I was ready to see if there was maybe something I did wrong. I took apart 25 rounds, and weighed every charge. All charges seemed to be within .1 to .2 grains of what I measured, but there were 4 that were off by as much as 2.2 grains! What the hell?!? So I grabbed my balance scale, and gave it a once over, checked some test weights, all seemed ok. So I measured a few powder charges, first on the digital, then the balance scale. first two were very close to perfect, but the third wasn't. I topped the weight on the balance scale and remeasured on the digital, 1.6 grains over. Re calibrated, remeasured, same deal, Checked out the scale again, and there was a tiny bit of crap in the area the balance bar pivot sits. rechecked several loads, no major variance. The 20 gram test block must have been heavy enough to move past the gunk, but a small charge sometimes didn't.

I thought I would add this to this post, first to explain what seemed to happen, and maybe save someone from the same mistake. Working near max recommended loads, that extra 2 grains could have been catastrophic.

Note to self. Keep your gear spotless.
 
What I do to see how stable powder is.... This time of year is perfect as the mornings are cold, near frost actually, then ramp up to mid teens by noon.

10 to 15C spread is plenty to see if the load is going to change.

Whatever your best load is for warmish weather, load up in 0.1gr increments to 0.5gr more (yes, you need a good scale for this).

Start when ambient is cold and see what loads shoots best. Did you find a load with MORE powder shot best?

Wait until ambient heats up to max for the day. Record the difference in temp. Shoot again. Were you back to your original warmish temp load as best?

If you see a need to adjust your load over a 10 to 15C range, that powder is going to be a royal pain for competition.

Many powders that are suited to competition, really don't change much over 20C spread. Speeds, vertical, grouping all stay the same.

This test also applies to all other parts of your rifle. If you find changes tied to temp, that system should be tweaked if competition is the goal.

Jerry
 
You must log in or register to reply here.
Back
Top Bottom