OK- I am still waiting for the final word--- will someone tell me whether the JP trigger and low mass hammer combo will work with military primers!  
I have heard that you may need to use the stock spring, but I'm just not sure--- anyone want to give me some installation tips for my Bushy?  I already know to use some purple thread locker on the trigger adjustment screws.  

Your best bet would be to contact JP directly, since it's their product!

You have their contact info?  My trigger kit hasn't arrived yet, but I am filled with excitement already. [8D]

yes.  if you use the hammer spring that came with the rifle.
maybe if you use the "yellow" low power hammer spring that came with the trigger kit.

go a google search for JP enterprises

www.jpar15.com

DPMS also installs them in their rifles...so, you can ask the DPMS rep over in Industry....

I used my standard springs and have not had any problems firing SS109.  I am very happy with the trigger.

I have the JP trigger and if the South African(luv that stuff) has the same primers as you are talking about then it should work just fine.

hey ARchoo- do you have the low mass hammer from JP as well, using the yellow spring for the kit?  

I have a feeling the hard primer problem may be nonsense (at least I hope it is)  
I will try it anyway, and see for myself this weekend.  Will keep you fellas posted!

I have had no problems with mine being too light.

yes and yes

I put the JP reduced power springs in the tactical rifle I just finished, and yes they had a problem with military primers using the standard parts kit.

This is where it gets interesting.

In order to get consistent ignition with military primers, I took the advise of several board members and ordered the JP low mass hammer.  I have used their triggers for years, but had no experience with their hammers.  I ordered the part from Brownells, and when it arrived I found it to be.....THE WORST POS I HAVE EVER BOUGHT FOR AN AR.  The machining was terrible; you could still see the machine marks on the engagement surface.  No part of the trigger was polished.  Installed, the trigger felt as if you were dragging a knife across a coarse metal file; not what you would expect for a custom $50 hammer.  I knew that JP must have just let a part slide through their QC, as this could not be indicative of their company's products.  I contacted JP directly, and told them of my problem.  They apologized and said that they would send me a replacement.  The gentleman even said he would "pick out a good one".  He also requested that I send the other hammer directly back to them, although "I" would be required to pay the shipping.  The replacement hammer arrived, and guess what?  The second hammer was just as bad as the part I ordered from Brownells.  I was afraid that it may be a problem with my rifle or other parts, even though I'm using a Bushmaster parts kit in my CAVARMS lower.  I tried the hammer in my other AR's, and even had a friend evaluate the part to offer an unbiased opinion.  The conclusion from all this testing was that the JP part was junk.  As a comparison, even the Bushmaster Mil-Spec hammer sear engagement surface is polished mirror smooth.

I'm going to ship the original part back to Brownells tomorrow and ask for a refund, and then I'm going to ship the replacement hammer back to JP.  I can say that I'm extremely disappointed/dissatisfied with JP.  I guess if I want a low mass hammer I'll have to break out the dremel tool.  I certainly couldn't do any worse than JP.

NEVER had a light strike with my JP trigger, Reduced mass Hammer, and reduced (yellow) spring.

I have had an exceptional trigger system since I installed it.

Good luck

TXLEWIS

I run JP triggers and springs in two of my AR's, but don't use the low mass hammer. The only time I had a problem was with the SA mil ammo. Everything else goes bang, even Wolf.

BTW, JP says it will set off all US primed ammo.