This is cross posted on another forum by me. If this is not permitted, please remove post.
Greetings!
I am attempting to assemble a load for my 380 (a Glock42), but I am encountering a couple of stumbling blocks.
What I have available:
Sierra 90gr JHP-V
Hornady 90gr JHP
WW231
Alliant Bullseye
I had assembled about 40 of the Sierra 90gr JHP on top of 2.9gr of WW231. At about 10 yards I was able to put all 40 rounds in a 4" group, shooting POI/POA. The problem was, the load was not potent enough to cycle the action. My dilemma is, Sierra lists 3.1gr of WW231 as maximum, which gives me very little flexibility for charge variation. According to the Sierra manual, 3.1gr WW231 is a maximum load, generating 970 fps when loaded to a COL of 0.940". According to Hornady, their maximum load of WW231 (3.6gr) with their 90gr JHP loaded to a COL of 0.965 will produce a velocity of 950 fps. The 2 bullets APPEAR to be similar, the difference being the powder charge and the COL.
Based on the Sierra data, I have a 0.2gr window for getting my G42 to cycle. Considering that I am working with what I have, has anyone that has loaded for the G42 experienced problems if you have approached 3.2gr with the COL of 0.940", or have you had to increase the COL in order to avoid excessive pressure?
As always, thanks in advance for your help!
Let’s stop for a minute and talk about differences in data versus powder lots as well as differences in “stickiness” of the bullet in the bore.
First off, the charges listed in loading manuals are nominal charges with maximums based on pressure testing in a pressure barrel and or a piezoelectric strain gauge placed on a barrel.
The precise charge needed to generate a certain pressure or velocity will vary a bit based on the actual powder lot. Canister grade powders marketed for Handloading are much more consistent than the bulk powders used by commercial ammunition manufacturers, but there is still a fair bit of variation in some powders.
The data in the Hornady 11th edition for Winchester 231 and HP-38 are good examples. Win 231 data shows a max charge of 3.6 grains and a velocity of 950 FPS in the 3.88” Beretta 84F. In comparison HP-38 shows a max charge of 3.5 grains and a velocity of 1050 FPS in the same pistol. Obviously the specific lot of HP-38 used for load development for the manual was faster burning and developed more pressure than the specific lot of Win 231 used for load development in the same manual and in the same test pistol.
Here’s the rub. Hodgdon has confirmed that Win 231 and HP-38 are the same powder made in the same batches and just labeled differently.
For the slow kids in the class that means that the data for Win 231 and HP-38 and there relative performance would have been reversed in the manual had Hodgdon just labeled each of the powders used by Hornady differently when they were packaged.
Colloidal ball powders like Win 231/hP-38 are much faster (about 2 weeks start to finish versus 6-8 weeks for a flake powder) to produce and are less expansive to produce, but they tend to have a bit more variability in their burn rate traits. Basically, a ballistician takes different lots of ball powder made to the same general but still very broad range of characteristics and blends different lots to get burn traits that are closer to the target specifications.
The end result is that you still get a bit more variation with colloidal ball powders (even when they have been rolled and flattened like Win 231/HP-38) than you get with a flake powder like Bullseye.
You need to keep that variability in mind when you develop loads with a ball or flattened ball powder. I’m also a strong advocate for using a chronograph when developing loads to get a better feel for how your load compares to what’s in the book, and in turn to get a better feel for what should be a max load with a given lot of powder.
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My favorite examples of internet myths in this area are the folks who quote an exact change of powder to duplicate a military load. Consider someone who pulls down a few rounds from a single lot of M72 match ammo and weighs the charge to find it is exactly 46.5 grains. What does that really mean?
You can verify that M72 match ammo used IMR-4895 with the 173 gr FMJBT bullet and a number 34 military primer. However based on pull down information, you’ll also encounter someone claiming that the powder charge was exactly 46.5 grains. You might also find a government source listing a *nominal charge* of 46.5 grains. That confirms it right? Well...no.
You need to understand that *nominal* is more or less *ball park* in this context. The actual charge needed to get the specified average velocity at 75 ft may vary from around 46 to 47 grains. Using 46.5 grains with a faster burning lot of IMR 4895 where the actual charge needed to be around 46.0 grains will produce excessive pressure.
M193 ball loads and surplus powders are even more interesting. Originally M80 ball for the M14 and M60 used a nominal charge of WC846 powder. When an economic and mass producible load was being developed for M193 ball for use in the M16 they started with WC846. However they found that only specific lots of WC846 on the faster burning end of the specification would give the required velocity at an acceptable pressure.
The end result was a narrower specification for use in M193 ammo and naming that new subset of the wider WC846 specification WC844.
Fast forward a few years and you started seeing canister grade powders labeled BLC-2 and H335. Inevitably folks started calling them canister grade equivalents of WC846 and WC844 respectively.
And of course it follows theyyou will see people claiming you can use BLC-2 data for WC846 and H335 data for WC844. You’ll also see them quote exact powder chargers to duplicate M193 and M80 ball loads using H335 and BLC-2 based on pulling down of a few of those military loads that had WC846 and WC844 powder.
The whole process ignores the large variation in lots of WC844 and the HUGE variation in lots of WC846. They either forget or more likely were never aware that load data was adjusted for each 10,000 pound lot of those bulk powders received by the ammunition plant.
They also ignore the variation in canister grade BLC-2 and H335 that requires some adjustment in precise powder charge when you change lots.
Worst of all you’ll see people buying pull down WC844 or WC 846 powders. That only works if all the powder in that pull down lot came from the same lot of ammunition. Remember how the powder lots varied? Guess what happens when you start mixing pull down powder from rounds that were produced from two, or three or several lots of WC846. The random mix of powders in random percentages you end up with may not give you WC846 burn traits, and it may well not be mixed uniformly so it won’t be consistent.
I’m not opposed to buying surplus WC844 or WC846 powder but it need to be surplus in the manufacturer sealed keg or barrel before I’ll pay good money for it.
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Bullet wise how “sticky” a bullet is on the bore depends on a number off factors even when bullet weight is identical:
- the actual diameter of the bullet;
- the make up of the jacket alloy;
- the thickness of the jacket;
- the alloy and hardness of the core; and
- the bearing surface of the bullet.
There will also be variables related to your bore, land and groove dimensions.
In short, there is a lot more to it than just ,arching bullet weight and general appearance. Anytime you substitute a component, whether it is the bullet, the primer, the case, or even a different powder lot, you need to back off a bit and work back up to your target velocity.
