New Set-Up......

[MikieM]

Here's a couple of pics of my newest incarnation for PCC. I have been using the Taccom ULW barrel with success, but thought I'd try something new.

It's a Faxon 8.5 inch barrel with a comped Taccom 8 inch barrel extension, and a Taccom ultra-light hand guard. As you can see. in these really poor photographs, I have cut a hole in the top of the hand guard to allow the remaining gas to vent. My weak hand does not get in the way of this vent hole.

I think the mid-comp idea is sound, but time will tell. My only determination as to whether it works, or not, is how much the dot moves.

I chose the the 8.5 inch barrel because it should allow me to easily make PF, and not add additional weight. The gun now weighs 5 pounds 13 ounces without a magazine, and is easy to maneuver.

Hopefully I'll be able to shoot it this week. It's starting to get a bit chilly around these parts.

Mike.

 

[Les Snyder]

Sir... how can you possibly work with such a clean bench....

[MikieM]

Thanks for the compliment, but my work bench is not near as clean as my reloading bench across the room. 

 

 

[Tasteslikechicken]

Nice setup!


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[L9X25]

Is the port in the handguard smaller than the ports in the comp?  

 

I would make the handguard ports at least equal, likely larger, in the comp port.

  

Maybe the angles are not letting me see the actual hole sizes?

[MikieM]

The short answer is; the vent is slightly smaller than the comp opening, but I don't see it as a problem. There is about a 1/4 inch of space (on the inside) between the top and bottom of the comp and the hand guard, so some of the gasses will vent out the barrel end. The hole in the top of the hand guard is there for that first large burst of gas. Also, I can enlarge the hole if necessary. 

Edited November 13, 2017 by MikieM

[gerritm]

What loads are you thinking of to make this work? Looks like a great idea.

 

gerritm

[MikieM]

27 minutes ago, gerritm said:

What loads are you thinking of to make this work? Looks like a great idea.

 

gerritm

 

At the moment I'm using 3.8 grains of WSF under a Precision Delta RN seated to 1.125 inches. This load is for experimenting. I'll find something more definite come Spring, when I can get out and chronograph some loads.

My belief is that a slower powder would be more suitable for comp use than a faster one, such as Titegroup, but that is yet to be etched in stone.

Also, the mid-comp should allow the barrel to make enough pressure to reduce muzzle rise, as well as achieve desired PF, as opposed to a 16 inch barrel where the gasses are all but spent by the time they reach the comp on the end. At least I believe that to be true. Time will tell.  

[L9X25]

When the gasses vent out of a comp port or popple hole, they expand as they exit.  The pattern is similar to the shape of a V.  Any gasses that hit the inside of the handguard would be negating a portion of downward force of the comp or hole.  If there were no exit hole in the handguard, the effect of the comp applying downward pressure would be between minimal and non-existent.   Look at what BMILLER did on his for reference.

 

[MikieM]

I'm not so sure. 

The Taccom comp is square in shape due to the milling process and I believe that the jet follows the contour of the shape it impinges against and in this case the pressure wave would hit the bottom, sides, and the small amount of metal around the exit of the comp, and divert vertically. They may dissipate toward the side as they loose velocity, but they are of no importance then anyway.

If anything the hole in the hand guard should probably be equal in dimension to that of the comp, but who knows. I think I'll get to test it this afternoon so I'll get back later. 

[gerritm]

1 hour ago, MikieM said:

 

At the moment I'm using 3.8 grains of WSF under a Precision Delta RN seated to 1.125 inches. This load is for experimenting. I'll find something more definite come Spring, when I can get out and chronograph some loads.

My belief is that a slower powder would be more suitable for comp use than a faster one, such as Titegroup, but that is yet to be etched in stone.

Also, the mid-comp should allow the barrel to make enough pressure to reduce muzzle rise, as well as achieve desired PF, as opposed to a 16 inch barrel where the gasses are all but spent by the time they reach the comp on the end. At least I believe that to be true. Time will tell.  

Having shot open and played with loads enough to know slow powders are the way to go to get it to work, but will you have to increase to major or close to really have a effect? If you don't is there a powder that will give you the gasses at lower amounts and still keep the gun fairly clean? We have played a little with HS-6 and it is way too dirty at minor amounts.

 

gerritm

[L9X25]

Mikie,

Remember that, even within the comp, the gasses are still relatively under pressure.  As they escape from an area of higher pressure, to an area of lower pressure, they will expand in all directions, thus the cone pattern.  

 

WSF was intended to be a cleaner alternative to replace 540 (HS6) and it is certainly cleaner.  It does not have the high pressure stability of 540/HS6, but that does not come into play with minor velocity anyway.

 

 

[Screaminyz]

You could tape some paper over the hole and see how easy the gas blows through it, just to get an idea if the whole is large enough.


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[L9X25]

1 hour ago, Screaminyz said:

You could tape some paper over the hole and see how easy the gas blows through it, just to get an idea if the whole is large enough.


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Or plug the area between the sleeve and handguard with paper and see if it blows the paper out.  If the top vent is restricting flow, it will search for other ways out of the handguard. 

[MikieM]

I pretty much agree with all of you. Comps at minor velocities are iffy, at best, and probably unnecessary at 16 inches. 

However, you'll remember that this is an 8.5 inch barrel with a comp in front. There is still a fair amount of gas still pushing the bullet towards the end of the barrel.

I was able to go to the range an hour ago and shoot a couple of 47 rounds mags through it. I wish Tim Ubl would step in here and tell us what his testing has shown, but for me the criteria was simple. To best judge how much, or how little, the dot on the C-More moved.

So, after 97 rounds I'll describe it this way. When the gun fired the dot kind of wobbled and then rapidly returned to center. A crude description, but it's the best way to put it. I think it works.

After shooting I did feel that the opening in the hand guard was too small, like L9X25 had pointed out, so when I came back home I opened it up. (See photos).

I also laid my handkerchief over the opening and fired one off. You can see that gasses were coming out. 

All in all, I believe that there is some validity to a mid-comp, but how much remains to be see. More tests coming.

Accuracy was outstanding, by-the-way.

 

[L9X25]

Looks good, really good.  The way you have it now, if the gasses make contact with the handguard, it is just incidental.  The vast majority of the flow is exiting through the hole.

 

If you wanted to see how far you can go, try some 3N37 or N350 and see how that feels.  Likely will feel really good, burn really clean, and be 50% more expensive!   

 

Good Job!

[dmshozer1]

4 minutes ago, MikieM said:

I pretty much agree with all of you. Comps at minor velocities are iffy, at best, and probably unnecessary at 16 inches. 

However, you'll remember that this is an 8.5 inch barrel with a comp in front. There is still a fair amount of gas still pushing the bullet towards the end of the barrel.

I was able to go to the range an hour ago and shoot a couple of 47 rounds mags through it. I wish Tim Ubl would step in here and tell us what his testing has shown, but for me the criteria was simple. To best judge how much, or how little, the dot on the C-More moved.

So, after 97 rounds I'll describe it this way. When the gun fired the dot kind of wobbled and then rapidly returned to center. A crude description, but it's the best way to put it. I think it works.

After shooting I did feel that the opening in the hand guard was too small, like L9X25 had pointed out, so when I came back home I opened it up. (See photos).

I also laid my handkerchief over the opening and fired one off. You can see that gasses were coming out. 

All in all, I believe that there is some validity to a mid-comp, but how much remains to be see. More tests coming.

Accuracy was outstanding, by-the-way.

 

How far were the targets you were testing for accuracy and what size were the groups?

Not in your case but a great test to see if a comp is working is to hold the comp about 1 to 2 inches from a paper target. Pull the trigger. If

the bullet hole has just a little grey around it. It's working! If it shows lots of grey, you have a cool looking thing on the end of your rifle!

I have found that the exit hole on most comps are too big. About .040 larger that the bullet diameter is about right. At least in my experience

[MikieM]

I remember that test, now that you mention it. I'll try it next time down.

The other reason I went to the range was to verify my zero since I have a match coming up this Saturday. I like to be dead on at 15 yards. Also, I don't use a rest. I prefer to shoot off-hand because that's how we shoot our game in real life. I easily put nine out of ten within a 3 inch circle and most of them were touching each other. The one that flew out was surely the gun, or ammo, and not me. Right? 

[ChiefArmamentGroup]

Mikie, great thread. What made you start tinkering with the mid-length popple-port? I mean I know its been around for years on open guns. Was real big back in the day. But it seemed that they started going away from that and just hanging comps on the end. Watching this thread has really got me thinking about the theory behind this and if there is something to be had there with a barrel that short. Obviously its working for you with the photograph of the handkerchief. How would you compare this with a full length barrel and comp at the end?

 

I wonder too if a comp is really doing that much on the end of 16" barrels with minor PF loads. Im looking at trying a few different ones out there just to test and get personal feedback. Currently I have an older DSG on there but thinking of switching to maybe a JP 3-port or MBX. The MBX looks interesting. I will keep an eye on how this develops. Might have to start tinkering myself. Good luck!

 

Chris

[MikieM]

I only recently started using the mid-comp, but the idea seemed more reasonable than any thing so far. The real pioneer in this regard is Tim Ubl, owner of Taccom. 

Here's the way I look at PCC, and mind you I'm new to the game and still learning. There are two things that are of prime importance to be successful. One: The gun should be as light as possible, Two: There should be as little recoil as possible.

As for number one, we now have the parts available to build a gun as light (possibly less) as 5 pounds. This particular gun here started out at exactly 5 pounds without a magazine when the Taccom ULW barrel was on it. It has since morphed to where it is now, 5 pounds 13 ounces. 

So what's wrong with a 5 pound gun? Well, mine was just a tad bouncy at that weight, although it worked fine. To correct the bounce I went to an 8.5 inch barrel instead of the 5.25 inch barrel that was in the ULW. This meant more weight, which reduces bounce (recoil), plus I am able to effectively burn less powder (without sacrificing power factor) which also means less recoil.

The use of a comp (mid-comp in my case) was to hopefully further reduce recoil. Again, the word recoil is in reference to the amount of dot movement in the optic. These guns don't move a whole lot anyway, but less movement of the red dot means less time on target and better splits. Less is best, and we all have a need for speed.

Let me edit this by also saying that in looking at the Bullet by the Inch charts, I could see that the bullet velocity (in most cases) had just about peaked for the 9 mm in a 16 inch barrel. So you might say it had run out of gas by the time it got to the comp. This made the comp on the end of a 16 inch barrel nothing more than extra weight. Weight we don't need.

 

 

Edited November 14, 2017 by MikieM

[MikieM]

7 hours ago, L9X25 said:

Mikie,

Remember that, even within the comp, the gasses are still relatively under pressure.  As they escape from an area of higher pressure, to an area of lower pressure, they will expand in all directions, thus the cone pattern.  

 

WSF was intended to be a cleaner alternative to replace 540 (HS6) and it is certainly cleaner.  It does not have the high pressure stability of 540/HS6, but that does not come into play with minor velocity anyway.

 

 

 

Quite right. With the 5.25 inch barrel (ULW) there was unburned powder through out the action. With the 8.5 inch barrel there is only soot. Soot is good.

[MikieM]

7 hours ago, gerritm said:

Having shot open and played with loads enough to know slow powders are the way to go to get it to work, but will you have to increase to major or close to really have a effect? If you don't is there a powder that will give you the gasses at lower amounts and still keep the gun fairly clean? We have played a little with HS-6 and it is way too dirty at minor amounts.

 

gerritm

 

Whether the comp on a PCC is effective at minor PF is still debatable, but I think it is. Especially in a short barrel with a comped extension.

The reason, of course is gun weight. The weight of most Open guns are what, around 44 to 46 ounces? Give, or take?

A PCC is easily twice as heavy so less gas out of the comp is needed.

[ChiefArmamentGroup]

22 minutes ago, MikieM said:

I only recently started using the mid-comp, but the idea seemed more reasonable than any thing so far. The real pioneer in this regard is Tim Ubl, owner of Taccom. 

Here's the way I look at PCC, and mind you I'm new to the game and still learning. There are two things that are of prime importance to be successful. One: The gun should be as light as possible, Two: There should be as little recoil as possible.

As for number one, we now have the parts available to build a gun as light (possibly less) as 5 pounds. This particular gun here started out at exactly 5 pounds without a magazine when the Taccom ULW barrel was on it. It has since morphed to where it is now, 5 pounds 13 ounces. 

So what's wrong with a 5 pound gun? Well, mine was just a tad bouncy at that weight, although it worked fine. To correct the bounce I went to an 8.5 inch barrel instead of the 5.25 inch barrel that was in the ULW. This meant more weight, which reduces bounce (recoil), plus I am able to effectively burn less powder (without sacrificing power factor) which also means less recoil.

The use of a comp (mid-comp in my case) was to hopefully further reduce recoil. Again, the word recoil is in reference to the amount of dot movement in the optic. These guns don't move a whole lot anyway, but less movement of the red dot means less time on target and better splits. Less is best, and we all have a need for speed.

Let me edit this by also saying that in looking at the Bullet by the Inch charts, I could see that the bullet velocity (in most cases) had just about peaked for the 9 mm in a 16 inch barrel. So you might say it had run out of gas by the time it got to the comp. This made the comp on the end of a 16 inch barrel nothing more than extra weight. Weight we don't need.

 

 

I tend to agree with almost every aspect on this except the weight part. I can see it going both ways really. Granted it might be like comparing apples to oranges, but a full steel 1911 shoots a heck of a lot better than one of the scandium versions. More weight to "absorb" that recoil. 

 

In regards to PCC, the only part that really moves is the BCG and buffer system(over simplification, I know). I can see how a lighter BCG would be beneficial as it is less reciprocating mass (basic physics, right?). So the lightest weight possible while still allowing the gun to cycle properly makes sense. I've seen a lot of numbers thrown around, but for the most part the 19-20 numbers for both BCG and buffer seem to be pretty consistent. It really comes down to the ammo you run. Factory ammo would be closer to major PF numbers while loads tuned to the PCC world would be closer to the 130-140 PF range.

 

You citing that the 5lb rifle was a little too snappy seems to agree with the too light version= too snappy comparison with the 1911s. Kind of like trying to find just the right balance it seems. So would a 6lb 16" barrel with a hefty comp actually be beneficial? More so because of the weight at the end of the barrel than actually the ports working. Akin to a tungsten guide-rod for a 1911 or a full length dust cover. 

 

Chris

 

 

(Sorry if it is a hectic post. Got a lot of different things running through the head. Tough to get it on paper in an orderly fashion. haha)

[dmshozer1]

2 hours ago, MikieM said:

I remember that test, now that you mention it. I'll try it next time down.

The other reason I went to the range was to verify my zero since I have a match coming up this Saturday. I like to be dead on at 15 yards. Also, I don't use a rest. I prefer to shoot off-hand because that's how we shoot our game in real life. I easily put nine out of ten within a 3 inch circle and most of them were touching each other. The one that flew out was surely the gun, or ammo, and not me. Right? 

Absolutely,

All flyers are the gun!

[MikieM]

47 minutes ago, ChiefArmamentGroup said:

I tend to agree with almost every aspect on this except the weight part. I can see it going both ways really. Granted it might be like comparing apples to oranges, but a full steel 1911 shoots a heck of a lot better than one of the scandium versions. More weight to "absorb" that recoil. 

 

In regards to PCC, the only part that really moves is the BCG and buffer system(over simplification, I know). I can see how a lighter BCG would be beneficial as it is less reciprocating mass (basic physics, right?). So the lightest weight possible while still allowing the gun to cycle properly makes sense. I've seen a lot of numbers thrown around, but for the most part the 19-20 numbers for both BCG and buffer seem to be pretty consistent. It really comes down to the ammo you run. Factory ammo would be closer to major PF numbers while loads tuned to the PCC world would be closer to the 130-140 PF range.

 

You citing that the 5lb rifle was a little too snappy seems to agree with the too light version= too snappy comparison with the 1911s. Kind of like trying to find just the right balance it seems. So would a 6lb 16" barrel with a hefty comp actually be beneficial? More so because of the weight at the end of the barrel than actually the ports working. Akin to a tungsten guide-rod for a 1911 or a full length dust cover. 

 

Chris

 

 

(Sorry if it is a hectic post. Got a lot of different things running through the head. Tough to get it on paper in an orderly fashion. haha)

 

I originally thought that tuning the bolt group and plunger spring was key to a flat shooting PCC. I no longer think that. I believe that a light bolt and a reasonably stiff spring is best. I currently use the Taccom bolt with a Blitzkrieg Blue spring and it all works fine. No feeding problems what-so-ever.

To me the best approach for making it all work properly is the right load for the barrel you're using. Currently I'm using WSF, but only because I have a bunch of it on hand. In a 16 inch barrel it's easy to make PF with bunny fart loads, but the price you pay there is added gun weight. 

Let me say this about gun weight whilst we're talking about it. Some guys like a heavy gun. Many of you youngsters out there have no problems at all lugging around a 6 and a half to 7 pound PCC, but guys like me have to conserve energy and light guns are one way to do that.

Anyway, I do have a few pounds of N320 to use that I think would be perfect in the 8.5  comped barrel. My other gun has a 10.5 inch non-comped barrel, and either the N320, or the WSF should work fine.