9 major load with HS6

[levellinebrad]

Good morning all! I’m up this morning looking for some knowledge and understanding of HS6. I’ve loaded many thousands of rounds 9major with 8.1 gr hs6, 124gr PDHP, at 1.165 and was achieving a 170pf. That was all out of 2 different CK open guns. I finally received my SVI open gun a couple of months ago and had thought that the load would work fine due to the fact that I have a friend with 2 SVI’s that are almost identical to my build who runs that load and getting about a 170pf. That load was however only making 162pf from my SVI. I bumped it up to 8.2gr and got to a 165pf and 8.4gr was a 164pf. I ran several strings of 6 shots and the results were the same. My chrono has always been spot on with every chrono at the several major matches  I’ve shot so I’m pretty positive that results are accurate so on to the questions.

 

1) what is it about different barrels that makes the same load either slower or faster?

 

2) Why would a load using .2 gr more powder result in a lower velocity?

 

3) does anyone load HS6 higher than 8.4gr

 

i have about 6lbs of HS6 that I’d like to use up and I like the feel of HS6 vs AA7. It seems to be a bit more snappy which I actually like. Thanks

 

[Hi-Power Jack]

Sounds like you're very experienced, so I hesitate to go back to basics, but :

 

When you change your powder charge, are you making the change, and then

running ten loads through before loading up the rounds to test ?

 

If you run some loads at 8.2 and then increase the powder to 8.4, it might

take a while for the load to register at 8.4  (you might be running some

more 8.2").

 

Is the powder measure half full, or more ?   That can make a difference .

 

Did you check the OAL to make sure there was no bullets being pushed

into the case (doesn't sound like that would be a problem, here, but

worth checking.

 

Are you using a single Headstamp (all WW's or RP's) ?

 

[levellinebrad]

22 minutes ago, Hi-Power Jack said:

Sounds like you're very experienced, so I hesitate to go back to basics, but :

 

When you change your powder charge, are you making the change, and then

running ten loads through before loading up the rounds to test ?

 

If you run some loads at 8.2 and then increase the powder to 8.4, it might

take a while for the load to register at 8.4  (you might be running some

more 8.2").

 

Is the powder measure half full, or more ?   That can make a difference .

 

Did you check the OAL to make sure there was no bullets being pushed

into the case (doesn't sound like that would be a problem, here, but

worth checking.

 

Are you using a single Headstamp (all WW's or RP's) ?

 

I do run through several cases of powder after changing a charge

 

powder dispenser is full

 

i did check oal.

 

i have always used range pickups which does give me some swing in velocity but not enough to make any real difference 

 

thanks for for the thoughts though.

[Guy Neill]

Different barrels - different dimensions.  Changes in the chamber diameter, leade (or freebore) and the diameters of the bore and groove all can have an effect.

 

 

[Part_time_redneck]

2 hours ago, levellinebrad said:

Good morning all! I’m up this morning looking for some knowledge and understanding of HS6. I’ve loaded many thousands of rounds 9major with 8.1 gr hs6, 124gr PDHP, at 1.165 and was achieving a 170pf. That was all out of 2 different CK open guns. I finally received my SVI open gun a couple of months ago and had thought that the load would work fine due to the fact that I have a friend with 2 SVI’s that are almost identical to my build who runs that load and getting about a 170pf. That load was however only making 162pf from my SVI. I bumped it up to 8.2gr and got to a 165pf and 8.4gr was a 164pf. I ran several strings of 6 shots and the results were the same. My chrono has always been spot on with every chrono at the several major matches  I’ve shot so I’m pretty positive that results are accurate so on to the questions.

 

1) what is it about different barrels that makes the same load either slower or faster?

 

2) Why would a load using .2 gr more powder result in a lower velocity?

 

3) does anyone load HS6 higher than 8.4gr

 

i have about 6lbs of HS6 that I’d like to use up and I like the feel of HS6 vs AA7. It seems to be a bit more snappy which I actually like. Thanks

 

 

My old now backup gun is an STI lower / SV upper with an Infinity ultimatch barrel. New gun was made by Matt Cheely. KKM barrel. Both guns run Matt's 4 port comp and both have 2 - 1/8" poppel holes. My load is 7.9g of HS6 behind 124g PD JHP's. CCI 500 primers loaded to 1.170. New gun made 171 PF at the MS classic. Using my chrono and everything being the same my backup with the same loads makes 168PF while still on my chrono new gun makes 171. My differences aren't as drastic as yours but my SV barrel is definitely a bit slower. 

 

When experimenting i think with 115's I was around 8.5-8.6g of HS6. Just my personal opinion but I wouldn't want to go higher than that with the 124's. I love and swear by Precision Delta for open, PCC, and CO, but it might be worth experimenting with something else. 

 

Im sure this is probably not the issue but couldn't hurt to borrow a small amount  of HS6 from someone else, verify results just to rule out powder contamination. Good luck. 

[36873687]

Every barrel is different. Once u get rounds on it also slow up. Every sv barrel I’ve shot is slow anyway 

[gng4life]

I had an old STI barrel one time and I had to go up to 8.6 HS6 to make 170 with a MG 124 JHP. Most of my others now only need 8.1-8.4 but I've loaded as high as 8.6. Watch for pressure signs - I'm sure you're aware of that but I wanted to mention it.

 

Also, I read one time when the increase in powder in a Major load failed to raise the velocity, there was a some sort of power curve issue that could be dangerous. That was years ago and I will try to look around for a reference but I would be extremely cautious with going any higher. Is there any unburnt powder residue with the 8.4 loaded rounds?

[EEH]

8.3 out of my Sti trubor,with two popple holes chro. at 176. With HS6 

new Sti dvc with two holes added = 8.1 HS6 gives me 170 

 

I tried some longshot powder got to about 165 pf. The more I increase powder charge pf. Went down, everyone said I had reached the max and more powder did not effect pf. 

Iv run a lot of hs6 never had that happen.

[levellinebrad]

I think I’ll just stick with the AA7. 9.8gr is giving me a 171pf and seems to be in line with a few other folks who are running it. I guess I’ll load some minor with the HS6 just to use it up

[EEH]

1 hour ago, levellinebrad said:

I think I’ll just stick with the AA7. 9.8gr is giving me a 171pf and seems to be in line with a few other folks who are running it. I guess I’ll load some minor with the HS6 just to use it up

Or you could just send it to ME.

[igolfat8]

Are you using a balance beam or electronic scale? I don’t trust electronic scales and only use beams.  Also I suggest you zero each and every time you use it.

[levellinebrad]

5 hours ago, EEH said:

Or you could just send it to ME.

I’ll bring it on the 1st Saturday if you really want it.

[levellinebrad]

1 hour ago, igolfat8 said:

Are you using a balance beam or electronic scale? I don’t trust electronic scales and only use beams.  Also I suggest you zero each and every time you use it.

I have both and use both, especially when working up a new load. I bought the electronic scale about 4 years ago and have never had a difference between the 2 in that time.

[igolfat8]

Take a load and place it on your electronic scale and note it’s weight. Now lift it off the scale then place the same load back on the scale and note the weight again. Repeat this about 5 times and i bet you will see different numbers. Every electronic scale I’ve owned or used has this inherent flaw. I just don’t trust them.

[echotango]

12 minutes ago, igolfat8 said:

Take a load and place it on your electronic scale and note it’s weight. Now lift it off the scale then place the same load back on the scale and note the weight again. Repeat this about 5 times and i bet you will see different numbers. Every electronic scale I’ve owned or used has this inherent flaw. I just don’t trust them.

I just did it 10 plus times and got the exact same weight every time. 

[igolfat8]

On 6/26/2019 at 6:14 AM, levellinebrad said:

 

 

1) what is it about different barrels that makes the same load either slower or faster?

 

2) Why would a load using .2 gr more powder result in a lower velocity?

 

3) does anyone load HS6 higher than 8.4gr

 

 

1) Every barrel is different:

from the bore ID of one barrel to another there is variation

to the way the rifling were cut

to the way the bore may have some slight taper

to the bore’s surface finish

to the unique coating that (may) or may not have been applied?

 

All these factors affect the bullet to barrel sealing and drag on the bullet which in turn affects the bullets velocity numbers you see on your chronograph.

 

2) You may be at the top of your load specs for your particular bullet / barrel combination. When you hit that palteau then loading more powder will  flatten the velocity and actually make it go the other way. That is the danger zone you want to avoid.

 

3) I have loaded higher but just because I or someone else has doesn’t make it right or safe for someone else to do. 

 

Have you slugged your barrel?

Edited June 27, 2019 by igolfat8

[igolfat8]

Just now, echotango said:

I just did it 10 plus times and got the exact same weight every time. 

Then you sir have a great scale!

[Maximis228]

SV barrels are known to be slower than every other major manufacture.

[Loudgp]

What primers are you all running with 9Major? Spp or Small rifle? 

[echotango]

49 minutes ago, igolfat8 said:

Then you sir have a great scale!

Gem Pro.  Nothing special, but not a $30 loading scale.  Also I have noticed your cell phone can be nowhere near the scale or it will change. 

[Hiroshi]

I’ve seen people run 9.0 grains of HS6 making about 172 pf.

[levellinebrad]

2 hours ago, Loudgp said:

What primers are you all running with 9Major? Spp or Small rifle? 

I am using SPP

[KellyB]

I am about to try HS6 instead of WAC. Good comments here.

[Joe4d]

well not a different barrel thing, I am looking at results from same gun.
Generally ladders run pretty proportional,, add X powder, get Y increase.   When you get results that plateau like your 8.2 and 8.4 loads, tells me you are spiking in pressure, and that bullet/barrel/OAL/ powder combo isnt gonna do what you want. 

[chase214]

I ran 9gr of hs6 with a 115 MG