Hot makes hot loads

[Viperdoc]

Loaded 800 rounds of 223 for my AR to go prairie dog shooting earlier this month. All were with the ball powder H335, which has shot well in my gun in the past, and has shown good accuracy. It is also easy to run through the powder measure, better than any extruded powder.

First load was 24.6gr of H335, CCI SR primers, new Lapua brass (resized, trimmed and chamfered), and Sierra MK 53. This load is way below the listed max, but in the prairie of South Dakota (75-80 degrees ambient), many of the primers were flattened and showed cratering.

Second load was Berger 64 gr varmint bullets with Wolf SR magnum primers and 24 gr H335- these loads consistently blew primers and had ejector marks on the case heads- way too hot. This load was 0.6gr below the listed max.

So, I thought I was being conservative with the loads, well below the listed maxes, but even then the ball powder H335 showed a lot of temperature sensitivity. Most of my previous load testing had been done at around 65- 70 degrees, but even the ten or so degree increase in temperature made a huge difference in pressure generation.

Looking for advice for next year: load with an extruded powder? Testing looks like H4895 doesn't do as well in terms of accuracy in my gun as well as H335, and certainly doesn't measure as well. Varget does not seem to be optimal for the lighter bullets, so what does this leave? Or, simply load with even less powder using H335?

Even with a Harrel's meter, the extruded powders seem to vary as much as 0.2-0.3gr between throws, while the H335 is always within 0.1 or less.

So, sacrifice accuracy in metering and go to a stick powder that doesn't shoot as well in my gun, or go to even lighter loads with H335? What else?

 

[kyreloader]

Either IMR8208XBR or the new AR Comp from Alliant. (Graf had it in stock the last time I looked). Both powders should work well with the lighter bullets. I know 8208 works well with 52g Amax bullets. ;D

 

[KevinThomas]

Viperdoc,

Bit of a nonsequitor here in assuming that just because an extruded powder doesn't measure as uniformly as does a ball powder that it won't shoot as well. They will, even if the charge weight shows a tenth or two +/- more variation than the ball powder. Given the light weight bullets you're using here, I suggest trying either Benchmark or H322. Both meter well (which again, I don't consider to be that much of a factor) and will deliver superb accuracy with 50-55 grain bullets in a 223.

The other point your post makes, albeit unintentionally, is that book maximums don't neccessarily equate to a maximum in your individual rifle, and that all true "maximums" need to be approached cautiously. Just like the manuals suggest. There is no built-in "safety margin" in any manual I'm aware of, and when it shows a max, it's because that load showed a genuine max in the test rifle.

 

[Nomo4me]

I loves me some Benchmark for my 223 bolt gun with 50 grain blitz king bullets. My load is at book max but I've seen no pressure spiking in hot weather.

Meters to within +/- .2 grains.

 

[NorCalMikie]

That's the main reason I load to the "lower" accuracy node. Nothing like having a little "wiggle room" in case it gets hot.
You don't have to be fast to be accurate.

 

[dennisinaz]

Kevin is spot on, try some Benchmark, it works really well. If you want to stick with ball powders, Ramshot TAC is pretty temperature stable but all powders are affected by heat, some are adversely affected by cold. I use TAC and Benchmark to exclusion in .222 and .223 with 40-50 grain bullets.

 

[6BRinNZ]

I use BM2 (Benchmark) in my .223, I don't think I have the temp extremes you guys get , but it does meter pretty good, better than 2208 (varget) and definitely better than 2206h (h4895).

10 degress doesn't sound like much for this level of increased pressure, certainly I deal with 10-15 degrees celsius of temp and don't have this problem using benchmark, varget or 2206h.

I did have a load that was shooting awesome and after 3rd reload I started blowing primers, turns out I was seating into the donut causing pressures to spike. The other time I had issues with primers blowing was when winchester changed from the silver to gold primer, same load blew the gold primers, not consistently say 1 in 5.

With factory rifles I have never had a problem staying within min and max (outside of issues above) of the ADI chart so I do wonder if something else is going on for you. (I am using bolt guns)

 

[762willdo]

2520 nuff said

 

[Viperdoc]

Thanks for the tips. My H335 loads with the Sierra 53 MK were at the lower node I found when shooting at around 55-60 degrees F, but clearly showed pressure signs at 78-80 degrees (ambient), which could've been even hotter in our vehicle in the shade. They were at least 1.5gr less than the Sierra book max for AR's, and I am running a heavyweight bolt with added weight.

TAC has shown promise in some of my trials, so I will work on these as well, and have never tried either Benchmark or 8208, so will order some of this as well.

I have used 2520 and Varget with heavier bullets 69 and 77 SMK, but I thought both of these were considered a little too slow for lighter bullets?

On another note, it seems like the primers are coming out pretty easy (I decap in a separate step). The brass is all new Lapua, and I always uniform the primer pockets after the first loading. Is it safe trying to reload the cases that have
popped the primers?

All the primers that blew were Wolf small rifle magnums. Could they be smaller than my usual CCI, which showed some flattening and cratering, but never blew?

 

[6BRinNZ]

hey Viperdoc - I wasn't suggesting to use varget, just making a relative comparison of metering abilities of Benchmark against other stick powders...

If you developed the load with 1 primer and are using another that could be compunding your issues.

Below is a link to CCI measurements...I don't have an equivalent for wolf

http://www.jamescalhoon.com/primers_and_pressure.php

Good luck

PS enjoying the PD articles...you guys are lucky...a 50 round day for me is huge...

 

[lloydx2]

Be carfull youll end up with a primer or primer anvil under the trigger. You dont want to pull the pins out in the field. If you feel a loose primer its done

 

[Scott Harris]

Were the book maximums listed specifically for an AR? Sierra has separate loading data for an AR that is 1.5-2.0 grains lighter.

 

[snowpro440]

If your loads were showing signs of excessive pressure you could always place your ammo in a cooler with an ice pack till your ready to shoot it ...

 

[Viperdoc]

I used the reference from the Sierra section on AR's. Good point regarding the loose primers- does anyone recommend pulling out the whole trigger group to look for loose primers?

Also great advice regarding cooling. However, we didn't have a cooler or ice, but did think about this.

Am going to redo ladders the right way with a chrono, but ran out of time prior to our trip. Will be using Benchmark, 8208, and TAC.

Hope to get this sorted out since may want to go again this summer, it was great fun.

 

[Ackman]

I stopped using H335 years ago but seriously doubt that only 20-25* temp increase will change a load that's comfortably in the safe zone into one that's overpressure. Letting 335 loads sit in the sun will do it though. And with H335 I've had significant differences from lot to lot.

 

[Scott Harris]

http://www.proneshooting.blogspot.com/

Look at Mike's notes below the 6/18/11 scores......exploded rifle using H335. Nuff said.

 

[7 loader]

Try IMR8208XBR. 23.5 start loads with a 50 gr nosler bt varmint I haven't found any temperature probs yet. 15 deg. to 95 deg.

 

[PJGunner]

Except for a recent one day run with H-335, I haven't used that powder since the mid 1970's. back then I used it with the 150 gr. Sierra in a Remington 660 with 20" barrel. Muzzle blast was ferocious and the ball of fire out the muzzle was brighter that the sun at high noon on an August day when I lived in Nevada. However, the load was one heck of a deerslayer in that rifle.

My only other experience with that powder was working up a 250 gr. bullet load for my .35 Whelan. It worked quite well with good velocity and better than average accuracy. Powder used was some H-335 left over from when I was using it in the .308. Price was still on the can and said, $3.75. I think I got it back in 1975.

One thing that keeps me out of trouble is I do probably 99 percent of my load work up in the summer. Not a lot of fun shooting under a tin roof when it 110 degres in the shade. If I should do a load work up during the colder months, it will get redone when it gets hot again. I feel this is one thing that has kept me put of trouble with potential overloads.
Paul B.

 

[Viperdoc]

I just received a pound of 8208 and Benchmark for working up with SMK 53 and Berger 64 varmint bullets, Wolf SRM primers, and all Lapua brass. Will do some ladders and then chronology the loads that come close to good nodes.

Also have TAC available to try as well.

Thanks to all for the advice.

 

[CZ93X62]

You have pretty clear over-pressure indications present. GI 5.56 brass can cause elevated pressures due to its thicker web area--I'm wondering if Lapua brass is thicker than other brass makes in 223 caliber. I have zero experience with Lapua in this caliber.

I'm very fond of H-335, WW-748, and WC-844 for the 223/5.56. I have yet to experience any of the pressure excursions you mention in bolt rifles or gas guns, and I live/shoot in 100*+ summer temps. Your load weights are indeed not excessive, in fact are quite reasonable. Something ain't right--and brass weight is the first place I'd look. This assumes there is at least .025" of leade clearance from your bullets' ogives. FWIW, the GI 5.56 chamber in my AR has over .100" of freebore before the rifling raises up--LOTS of clearance.