Loading WC-846 in 7.62x51
 

I came across some surplus 846 powder i bought a few years ago and decided to work up a load for my 308. I bought remington 150 grain FMJ-BT since they were on sale and Win primers were on hand. I searched for all the info I could find and settled on a starting load midway up the recommended range. I loaded 4 test batches in 1/2 grain increments. Then as an additional experiment I took 3 rifles to chronograph the results. At this time I wasn't interested in finding the most accurate, but instead, coming close to NATO spec velocities. The rifles I took to the range were a Rem 700-22" bbl, An almost new FAL-STG kit I built and a Springfield SAR-48 (Imbel FAL) both with 21" bbls.
I fired 5 rounds of each load thru each rifle using a PACT chronograph at 10' from the muzzle. I also fired some NATO surplus I had on hand as a control. (Headstamps were WRA, FNM & MAL averaged together). I expected some variance between the bolt action and the semi-autos but the results were surprising, showing that the STG held consistently higher velocities.

Before I list the results - note that all reloading disclaimers apply and I assume no liability for your stupidity or errors. You should reduce starting charges by 10% and work up incrementally, looking for signs of excess pressure - a subject you will have to learn about on your own.

I decided to go with 44.5 grains as a starting load with LC-67 cases. The specs for M-80 seem to indicate a avg muzzle velocity between 2750 & 2800 fps so this was my target.

Here is a summary of the average velocities with the extreme spread which was usually between the Rem and the STG.

WC-846
Load.....Rem 22".....SAR 21".....STG 21".....ES

Nato.....2766..........2781..........2849.......83
44.5.....2799..........2838..........2830.......31
45........2821..........2849..........2868.......4 7
45.5.....2866...........N/A...........2889.......23
46........2820...........N/A..........2910........90

Notice that the velocity from the NATO surplus is on the high end of the published spec thru the STG.
It seems surprising is that the velocities from the STG are considerably higher than the other rifles, especially the SAR. I just noticed that the gas port was wide open on the SAR while partially closed on the STG (#4) so maybe that is the diff ?

I also looked at the primers from each gun under a 10x microscope afterward to see if there were any signs of excess pressure. There weren't any significant indications but I did notice some irregularity starting to show up in the way the sides of the primers filled out into the primer pocket, next to the old crimp on the 46 grain loads. The 46 grain loads... one side was starting to spread a little more than the other side, but not by much. There was no signs of gas leak, cratering, flatening or other indicators. I did notice that the avg velocity of the Rem fell back somewhat.

Overall it was an interesting test and I think I will test some more between 44.5 and 45 grains to see which one is more accurate.
:wink:

Re: Loading WC-846 in 7.62x51
 

Interesting test. Is WC-846 the Gov't contract 7.62 NATO stuff? Where did you find data? Pressure curve optimum for FALs? I have heard some complaints that WC-846 tends to be a little "spikey" and IMR 4895 more linear as far as pressure curves go...

Personally, I don't see that big of a difference in your data between the FALs...maybe a little due to new barrel? If the gas port was wide open on the SAR, did it reliably cycle? How far did it throw the brass compared to the StG?

Re: Loading WC-846 in 7.62x51
 

Yes 846 is pulled down Military powder. I found data all over but mostly in threads over on the High Road forum or other gun boards. Google up a lot of threads and they all say about the same thing - each lot is different and needs to be test loaded. 846 is supposedly basically equivelent to BLc2.

Both the SAR and the STG are essentially new - say 200-500 rounds thru each of them. Both of them threw the brass in the same spot about 10' to 2 o'clock. Both were in the same group range on a 100yd target. Since I was shooting off-hand thru the chrono sky screens at the local gravel pit I was worrying more about not hitting my equipment more than a good group.

Another very interesting thing was the marks on each primer under the 10x microscope. I could tell which gun fired the round just by looking at the primer.
The rem had circular marks like concentric machining circles
The SAR had a pebbly appearance almost like a casting
The STG was beautiful, smoothly machined with one light small scratch
Every primer was unmistakable as to which gun it was fired in.

Re: Loading WC-846 in 7.62x51
 

Thanks. I own a few FALs myself, but haven't really tried reloading for them very much. Shoot mostly surplus. What few reloads I tried did well. IMR 4895 worked good and I plan to try some Accurate 2015 and some Varget, since I have a good bit. May try some other ball powders like Win 748 and Accurate 2460. Will keep you posted when I do. Regards, SC

Re: Loading WC-846 in 7.62x51
 

I think I would drop back to 44 grains on some of your test rounds and see
what they cronograph at.
Do any of the rifles you are going to use these in have floating firing pins?
I was under the impression you should use the CCI #34 primers for "Nato"
type ammo.

Re: Loading WC-846 in 7.62x51
 

Good point. I have used Federals almost exclusively over the years. They are softer, and I have gotten consistent results with them. I do have some CCIs around. I do believe CCIs are harder (even std) than most types...and harder primers for battle rifles is probably a good idea, although I haven't ever heard of it being a problem with FAL-types.

Re: Loading WC-846 in 7.62x51
 

Well, I'm not sure if the FAL firing pin is a floating type or not. Dropping back to 44 might get closer to the tested NATO velocities, and spec of 2750-2800, as I see I am a little faster than that.
Even though I swage the primer pockets, I find that CCI primers don't seat easily, deform, flatten and are generally dificult to work with. Winchester primers are marked for standard or magnum powders and seat easily and without problems. I generally buy Winchester these days and have no problems with their performance either. I am not staking or sealing them so I don't think it matters under the conditions I'm using them under. I have the SA battle packs for trying times.

Re: Loading WC-846 in 7.62x51
 

FALs have a rather heavy spring-loaded firing pin, so slam-fires are not an issue. I have also shot soft-primered Federal match without incident.

You will notice a tiny indentation on chambered rounds where the pin has lightly bumped the primer...this is very common in most all battlerifles, but like I mentioned earlier, I never heard of any problem with the FAL.