Slow Motion Comp Testing

[Gooldylocks]

Lightfighter> your video's show tip up of the muzzle as the gas is exiting the comp. This is usually a sign of not enough gas. HS-6 is lower on the gas production scale verses AutoComp. Try some AutoComp to see if it produces enough gas to get the comp working like it should.

9 grains of HS6, and you think that AC makes more gas? Don't buy it. AC takes a grain or more less to get the same pf, even if grain for grain it made more gas, I seriously doubt it would make up for the difference in charge weight. I'm betting grip is the issue.

[thompsoncustom]

Quote

9 grains of HS6, and you think that AC makes more gas? Don't buy it. AC takes a grain or more less to get the same pf, even if grain for grain it made more gas, I seriously doubt it would make up for the difference in charge weight. I'm betting grip is the issue.

ya that's kind of what I was thinking too, if you really want to produce more gas step down to a 115gr bullet so you can get above 10gr of powder

[Aircooled6racer]

Hello: I am using 8.8-9.0 grains of HS-6 with a 115 and that gives me 171-173PF. Auto Comp has less gas not more than HS-6 at the same power factor. It also hits the hand a little harder. Comp design does a lot as I have said before. Thanks, Eric

[Gooldylocks]

Hello: I am using 8.8-9.0 grains of HS-6 with a 115 and that gives me 171-173PF. Auto Comp has less gas not more than HS-6 at the same power factor. It also hits the hand a little harder. Comp design does a lot as I have said before. Thanks, Eric

Ding ding ding, we have a winner

[lightfighter363]

Just ordered 115gr Fmj. thanks guys.

 

[Hi-Power Jack]

1 hour ago, lightfighter363 said:

Just ordered 115gr Fmj.

Since the base of FMJ's is exposed lead, you'll end up cleaning your comp often ...

Easy to avoid by using JHP's.     

[lightfighter363]

1 hour ago, Hi-Power Jack said:

Since the base of FMJ's is exposed lead, you'll end up cleaning your comp often ...

Easy to avoid by using JHP's.     

 

Lol, ok next time i will get JHP.

[CHA-LEE]

7 hours ago, Gooldylocks said:

9 grains of HS6, and you think that AC makes more gas? Don't buy it. AC takes a grain or more less to get the same pf, even if grain for grain it made more gas, I seriously doubt it would make up for the difference in charge weight. I'm betting grip is the issue.

When I was testing 9 Major loads I tested AutoComp, SP2, and HS-6. Using 115gr JHP's and all of them making the same 171 PF. The AutoComp would make the dot to negative off the glass (Too much Gas causing the muzzle to dip as the shot fires), SP2 would also go negative but the dot would stay within the glass and HS-6 would allow the dot to rise slightly. This is all with the same Comp, Springs, and Grip Pressure. AutoComp makes more gas than HS-6 in my setup. Or should I say that the AutoComp load promotes the function of the comp more than HS-6. If its not gas volume causing the difference then it must be magic fairy dust.

Edited January 9, 2017 by CHA-LEE

[BeerBaron]

With your Kung fu action grip you don't need a comp in open chalee! You could just run a limited gun in 9 with a dot I reckon.

[ShortBus]

Chalee, your gun actually goes down when you pull the trigger? This makes me feel so sad about my grip lol

[BeerBaron]

ok, please don't laugh. This 240fps vid shows me how poor my grip is. my excuses are as follows:

have not shot for a month.
new gun and new steel grip (only 360 rounds through the gun at this point)
end of a long 5 hour shooting session out in the 90 degree heat 
carrying a muscular injury in my shoulders at the moment which meant my shoulder strength was way down (evident in my arm movement)
have not kept up my grip training for the last 8 weeks and I've no doubt my hand strength has dropped.

so all excuses for my crappy grip out of the way these are the details:

CK arms 'hardcore' open in 38 super
KKM barrel with 3 barrel holes and 4 chamber cheely/CK titanium comp (2 up facing chambers and an end chamber that exits to the sides)
load is 9.2gn of 3N38, 124gn frontier RN CMJ, fed small pistol primer, starline 38 super comp brass

A couple of notes apart from the user error. The gun is new and still VERY tight (in fact you can notice a few times it did not fully stroke and had a weak ejection - has a new aftec in there). The slide is very tight still. Also I do not know what hammer spring and recoil spring are in there. Once the gun is run in I'll change them after some testing. The hammer spring feels VERY heavy to me (like 20b+) recoil spring feels like maybe a 10 or 11lb. I like an 8lb variable usually. I will look at this once the gun is run in. I am sure my tiredness affected the performance. I watched a friend shooting it with better grip and it had barely any muzzle lift, just the slide moving back and forward.

Even with the slight lift in the video I can still follow the dot within the lens. It's hard to tell but the doubles in the vid are about 15splits so I'm running it pretty fast hence showing up flaws in my technique in 'hose mode'. 

I'm very happy with how the gun performs. Once I'm back actively training and not carrying an injury I'll make another vid and redeem myself.

In the meantime......

 

Edited January 9, 2017 by BeerBaron

[BeerBaron]

here it is at regular speed. hides my flaws much better! at least it gives an idea of the speed I was shooting. 

 

[niroth81]

Baron, It does look like your recoil spring is a little heavy, but agree you should let it run in before you change it.

I'd be more worried about the flames coming out of the chamber at the 5 second mark. They are definitely NOT from the comp.

[BeerBaron]

They are coming out of the barrel ports.

Got some cool stills. It's just timing that makes it look like the flame came out of the chamber. The jet of gas comes out the ports/comp and is blowing back towards me (headwind) and it flames out for the duration of 1-2 frames (~1/10th sec). 

Edited January 9, 2017 by BeerBaron

[niroth81]

Are you sure? They look a long way back, and in the second pic the gun is out of battery. If so that is a very curious gas flow. Port angled backwards?

[BeerBaron]

It's definitely out of the comp/ports. You can see the trail of gas/flame. I've got some more stills, just having trouble posting them from my phone. 

The wind is just blowing the gas/ flame back. In fact in the second still you can see part of that flame is being obscured by the scope. It's slightly to the left of the gun. 

It would probably be pretty hairy to shoot if it was jetting flames out the ejection port!!

[niroth81]

Well it looks bloody awesome.

[user293]

I gotta hit up the range today to adjust the sight on my svi. I'll be shooting some 3n38 with 124 PD. I'll try my best to get a video but I'm going solo so it may be tough with my phone. I'll post the video later today. 

[zzt]

cha-lee, it might be magic fairy dust, or there may be another explanation.  I don't have the answer, but I will tell you about my initial experiments with WAC and HS-6.

My first loads were developed for a 3-chamber comp with three large up ports and four very small side bleeders.  There were no barrel ports.  The gun was my CZ TS Open gun in 40sw.  I settled on 155gr bullets, becasue the 135s required more powder, and made more gas.  That comp could not handle the extra gas, so it hit your hand harder.

7.2gr of WAC produces 172.7 PF.  8.2gr HS-6 produced 173.8PF, so I consider the loads to be the same.  The recoil was sharper with the WAC.  With the HS-6 it was stupid soft.  Three buddies filmed my shooting both loads and they all said the HS-6 load shot flatter.  I noticed the softer, but I could not tell from dot movement whether is was flatter.  What I could tell is the HS-6 made a lot more gas.  I was shooting in a semi enclosed range with a roof over the shooting station.  I felt nothing when shooting the WAC load, but the HS-6 ruffled my hair from the extra gas bouncing down from the roof.  There is no doubt in my mind that HS-6 makes more gas than WAC for the same PF.

Dot behavior from the two loads was completely different.  The WAC load made the dot track straight up and down.  It didn't leave the glass, and assuming I had my grip pressure right, it returned to the same spot.  Lots more grip pressure and the dot would return low.  Extreme grip pressure and the dot would go down first.  The HS-6 dot behavior was completely different.  The dot jiggled and tracked up to the right.  The jiggling was enough that the dot was not defined while moving, whereas with WAC it was.  So I stuck with the WAC load.

[CHA-LEE]

ZZT> I don't think your .40 caliber testing with way heavier bullets is a fair comparison to 9mm Major using 115gr bullets. The weight of the bullet affects the power factor calculation way more than the velocity. Pushing 115gr 9mm bullets at 171 PF is a completely different animal than a 155gr .40 bullet at the same PF. 

[zzt]

Could be cha-lee.  I look forward to testing that theory when my 9mm tru-bore is complete.

[user293]

9.4 grains 3n38 124 gr.  PD jhp. 176-178 PF 9 major

slow mo kinda sucks but was the best my phone could do. 

Edited January 9, 2017 by user293

[BeerBaron]

12 hours ago, niroth81 said:

Well it looks bloody awesome.

lol, it does have some pretty flames.

these still should help. bare in mind even at 240fps it depends when the frame hits as to what part of the firing cycle I get in a frame. One frame has the hammer half way down for instance and the next frame has the slide just out of battery. but on a few shots it captures either just as the bullet is exiting or just after. 

this one you can see the flames and hot gas come out of the comp/barrel holes and then are blowing back towards me and a bit to my left.

enjoy the stills, I think they look cool.

the first one you can see how the flame out can travel.

the second one is the one that look like the flame is coming out the side of the scope!

The third one is cool, for anyone who doubts the split speed, that's the previous piece of brass still in picture as i'm firing the next round.

 

[BeerBaron]

that first one really shows the gas patter. The holes are drilled at 90 degrees but they are chamfered in a kind of oval (more chamfer front and back) which seems to act like a funnel or cowl and directs the gas up but also out wider front and back. It seems to fairly equally jet gas in a big funnel shape front and back. I'm positive nothing is coming out anywhere other than barrel ports, comp and muzzle.

here's 3 more stills showing what the comp and ports are doing.

 

[BeerBaron]

some of those pics are very early in the firing cycle (can see lots of gas coming out the barrel ports), some are a little later (fire in the comp, gas from ports and comp) and some are slightly later again (slide slightly out of battery, flame has traveled away from the comp either up in the air or back).