Load for 10.5 barrel with H110 and Sierra 175 HPBT
 

Looking for a decent Subsonic load for a AR15 10.5 barrel using Sierra 175gr HPBT and Hodgen H110.
Thank-You

I am running around 9.2 grains of H110 in PMC or LC formed cases with Wolf 223 primers, 175 SMKs, and OAL of 2.17".

Your chamber may obviously be different.

This keeps me in the low 1000fps range.

Can you tell me how many rounds down the barrel and what kind of groups are you getting?

The barrel is a 10.5 SS 1x8 twist made by Teppo Jutsu with about 300-400 rounds through it.

I am not getting great results with H110 as I get severe stringing issues.

I need to run a bunch of supersonic loads to see if it helps the barrel settle down.

I am now trying AA#9 and 2400 to see if that works any better.

So far AA#9 does not show nearly the vertical dispersion that H110 does.

Yes with my 10.5 SSK Upper and using H110 I am getting verticle stringing at 3-4" groups. Someone suggested smaller oal but I think I am going to try a diffeent powder.

I have experienced terrible vertical stringing with H110 loads, switched to lil gun and #9 and the problem went way.

I avoid H110 now.

Rancid, I think your posts were one of the many that made me try other powders.

What is your #9 load for 175s?

Ok with all of my load developement using Sierra 220 HPBT and AA1680, Hodgon H110, and AA#9 no 3 shot groups smaller than 2".
Coal is ok. Brass and primer the same.
AA1680 10.30-12.5 Worst groups at 3"
Hodgon H110 9.1-9.5
AA#9 8.6-9.0
I have a(SSK) AR-15 10" Upper on a RRA Lower Receiver. I am shooting this with a AAC Cyclone Silencer. The optics are a Nikon Monarch 4-16 with a Mildot reticle and Burris steel rings. All is tight and has never had to be retightened since build. Silencer is on tight as well.
Should I try a factory load that will give me better results

Try Lil Gun and 2400.

How does the rifle shoot supersonic loads?

Are you getting consistent velocites?

What charge are you using with Lil gun? I just purchased some and want to get started!

Milehipo,

Those 50 or 100 yard group sizes? Appreciate the information!

Mike

100 yard group sizes. Outside mid 50's off the bench/bags.