500JRH, 440gr Leadheads, Chronographed, Interesting Results

[seancass]

I finally got a chronograph, so I made up some test loads. I thought some of you here may be interested in the results.

Freedom Arms M83, 4 3/4" barrel,
Starline Cases, For heavy loads, mostly 500 S&W, cut down, but a couple 500JRH stamped cases made it into the mix. Light loads used 500JRH cases.
Bullets are Leadheads 440gr WFN-GC
Winchester Larger pistol primers.
85-, Sunny, 5mph wind in face, elevation: 5280ft-ish!
Chrono 12' from muzzle, Shooting Chrony Master Beta
I cut this from my typed notes so I included some of my "notes".

First up, The heavies. H110.

Charge: 27.0 gr weighed
Velocity, Ave: 1325
Notes: 2 shots, chrono issues, 1324,1326!


Charge: 27.5 gr weighed
Velocity, Ave: 1321
Notes: 1 shot, chrono issues.


Charge: 28.0 gr weighed
VA: 1316
ES: 7
SD:3.6
Notes: shot velocities: 1318,1319,1319,1312,1312, also: WOW!


Charge: 28.5gr weighed
Velocity, Ave: 1337
Notes: 1 shot, chrono issues.


Charge: 29.0 gr weighed
Va: 1329
ES: 12
SD: 5
Notes: no velocity increase over lighter charges, blame barrel length. Lots of unburned powder. Shot vels: 1324,1330,1330,1325,1336. Remove last shot and SD=3! Energy: 1725ftlb.Also: WOW!


Now the light stuff.


Powder: Aliant Unique
Charge: 12.0 gr thrown, Lee PPM [perfect powder measure]
Va: 1028
ES: 30
SD: 14
Notes: ind shots: 1016,1042,1012,1040,1028, energy: 1032ft-lb, two more shots later did 1066 and 1071. Ammo possibly sat in sun, got hot.


Powder: Aliant Unique
Charge: 12.0 gr weighed
Notes: No Data, chrono issues on all 5 shots.

Powder: Aliant Unique
Charge: 11.0 gr weighed on Hornady scale.
Va: 988
ES: 44
SD: 18
Notes: ind shots: 992,964,987,1007. energy: 953ft-lb


Powder: Aliant Unique
Charge: 10.0 gr weighed on hornady scale
Va: 924
ES: 22
SD: 8.6
Notes: ind shots: 917,922,939,917,924. again: WOW!


Powder: Aliant Unique
Charge: 10.0 gr thrown, Lee PPM
Va: 930
ES: 33
SD: 19
Notes: only 3 shots:941,941,908


Other notes: The difference between the 10gr and 12gr of unique was a Lot! 10gr was quite pleasant, could really relax and plink. at 12gr, it was back to the business of recoil!

This was a lot of work! The few chronograph issues I had were really frustrating, but I learned if you want 5-shots of data, bring at least 10 rounds!

3-5 shots isn't really statistically significant so I'll have to make up some more test rounds and try this again another day!

It's very interesting that I appear to have run out of barrel! Every heavy load shot essentially the same velocity. the 29gr load had a lot of unburned powder, but how do you argue with an SD of 5!?

I may try making some heavy loads with 2400 and 4227 just to see if the short barrel does better with them. Members of this site would have me believe it won't.

Accuracy: I didn't shoot any targets. I know this gun shoots and frankly without a scope I'm likely to be the weak link and the data would be essentially meaningless. Sometime I'll load up a large batch and do a string of targets. The operator just needs more practice.

p.s. I love my Chrony! As an engineer/nerd Data is my friend! Making data about ammo I made was ridiculously fun!

[paul105]

Seancass;

Just a couple of observations:

Move your chrono back a bit more – 5 or 6 long paces – seems to make a difference, especially with heavy loads.

I’ve always had the best results when the sky is overcast or cloudy or in the shade of a building.

You may need a hotter primer with H110. I think Jack H recommends CCI 350s. Hodgdon’s online data uses Fed 210’s in their .500 Wyoming Express Data. I’ve had good results with Fed 210s.

I suspect that you are the victim of bad chrono readings with the H110 loads. Practically speaking, not much to gain going from 27.0 to 29.0gr of H110 under the 440gr WLNGC – I do however understand the desire to explore the outer limits.

One of my friends has chronoed a very, very large number of loads using his Chrony with complte success/satisfaction. I’ve had the opposite experience with the three that I owned. I sent the last one back to the factory to be fixed and when it came back I was still getting bad reading, no readings, etc. A 320gr .45 slug fixed the problem for good. Chronos can be very frustrating.

Enjoy your chronograph and keep us posted as you continue this project.

Paul


PS -- For anyone interested, I called JRH gunsmithing today and asked if they had any 500 JRH brass. Short answer was no. If anyone knows of a source??

[seancass]

Paul, that's a good thought on primers. I have cci350's. I can see if a hotter primer does a better job lighting the fire. I switched to mostly using WLP's because they're "For Standard or Magnum" loads and I liked the convenience. Wouldn't hurt to experiment some.

I also suspect I won't see many overcast skies in western Colorado! Had to take what I could get today. Overall, it worked well, but those few errors were frustrating. Fortunately, the learning curve to acceptable results was pretty flat.

[subsonic]

It's hard to say why you didn't gain velocity with the larger charges, but barrel length is not the reason.

Has to be something going on with the load or chrono, as pressure should always increase with larger powder charges and that pressure will increase velocity, no matter the barrel length. You are either not getting more pressure for some reason or your chrono is fooling/failing you.

Let the arguments begin.

[Encore64]

Don't care to argue, too much of that goes on here anyways.

But, I agree with Seancass on both points. Working up loads and chronographing them all is a lot of work. Something to keep in mind when paying the bucks for an updated reloading manual.

Secondly, I have experienced the same results with H110/296 and Lil Gun powder. Even when loading for rifle length barrels. So, while ruling out barrel length, I still don't have a concrete explaination.

[cmillard]

i too have had this happen with H-110.

[500fksjr]

I have learned with H-110 that mag primers are a must...and secondly a new case or out to 3x on reloading so that you have "Great" neck tension...Then a very good crimp...all powder should be burnt from 3.5 inch bbl to 5.5 inch...fwiw

[subsonic]

If I had to point a finger it would be pointed at neck tension.

Just for grins, check your powder scale for accuracy and repeat 3rds of each load after marking each case with a sharpie to show powder charge.