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Posted: 2/25/2006 1:33:25 PM EDT
I am configuring a gun through Del-Ton and the PRI gas busting charging handle is $75 option. Is this item necessary is my question. Thank You
Link Posted: 2/25/2006 1:38:30 PM EDT
Great Questions. I've never had a case failure. I guess if I had I'd have an answer.
Link Posted: 2/25/2006 1:51:02 PM EDT
From the information about the unit, its my understanding is that it is to keep the gases and material from a cartridge from blowing back into your face. I can understand the importance of this with a weapon that is fired on automatic or if you tend to use ammunition that is dirty, but does the gas buster help maintain the weapons functioning and the life of the components is what I wonder about.
Link Posted: 2/25/2006 2:04:27 PM EDT

Originally Posted By Ravinger:
I am configuring a gun through Del-Ton and the PRI gas busting charging handle is $75 option. Is this item necessary is my question. Thank You



I can't imagine how even a case failure could result in "harmful blowback gas and oil particles from striking shooter's face and glasses." The rear of an AR is pretty solidly sealed, and the bolt locks quite securely.

22 years with ARs and M16s, and this sounds like a solution to a non-existent problem. Nor can I find any images that enlighten me as to how a charging handle would accomplish this task, other than mention of "ports to divert etc." They specify it works better with a suppressor. If you don't have a suppressor (And I've never encountered such a problem WITH a suppressor...blowback through the receiver would be an indication to slow your rate of fire or get a better suppressor, to me), I can't see ANY advantage.

The small images I see look like a standard charging handle with an oversized latch. You can get those anywhere for about $35.

I'd say save your $75 and use it on something practical--hard chrome bolt carrier assy, extra mags, a sight rail, front grip (If you like that sort of thing), sling, QD swivels...

If I'm totally off base, I appreciate any info.
Link Posted: 2/25/2006 2:07:05 PM EDT
Link Posted: 2/25/2006 2:13:57 PM EDT
The gun that appeals to me is the Del Ton 16 inch rifle kit. This is my first build and I want to do it right.
Link Posted: 2/25/2006 4:03:25 PM EDT
they are great for weapon systems that are 14.5" or under due to the increased chamber pressures and when using a suppresor! other that that I personally think they are not a nessesity...unless you like lots of CLP!
but they do add a little to the weapon though as far as looks and charging!!!
Link Posted: 2/25/2006 4:13:39 PM EDT

Originally Posted By SIMPLYDYNAMIC:
they are great for weapon systems that are 14.5" or under due to the increased chamber pressures



How does a short barrel increase chamber pressure? It should be the same--peak pressure being slightly after ignition and before projectile has traveled more than a fraction of barrel length. As far as I can figure.



but they do add a little to the weapon though as far as looks and charging!!!


Looks aside, I do like an oversized release as long as it's not big enough to bang into my chest.
Link Posted: 2/25/2006 4:44:49 PM EDT
the handle itself is great the gas buster part is not really needed till you go with short bbls. or surppressed.

shorter bbls. have less "time" for the powder to fully burn and settle down so it has to go somewhere.
Link Posted: 2/25/2006 5:15:27 PM EDT

Originally Posted By eklikwhoa:
shorter bbls. have less "time" for the powder to fully burn and settle down so it has to go somewhere.



Out the muzzle?

Sorry, I don't see any way to increase CHAMBER pressure without using a different load. Ambient barrel pressure, yes. I can even see residue in the barrel as the action cycles.

I can't see any way to get that residue through a solid receiver toward the shooter...ambient should drop to equilibrium when the ejection port opens. That's away from a right-handed shooter and there's a brass deflector there, too.

Anyone got any figures to plug in here?

Link Posted: 2/25/2006 8:07:10 PM EDT

With one it seems easier to pull the charging handle back. The larger surface area of the handle makes it smooth as silk.

The backend extends up over the top of the receiver and wraps below as well. I don't think my glasses get splashed with CLP as much as before, but I haven't done any tests to verify a regular CH was letting it vent.
Link Posted: 2/25/2006 9:12:51 PM EDT

Originally Posted By MikeWilliamson:

Originally Posted By SIMPLYDYNAMIC:
they are great for weapon systems that are 14.5" or under due to the increased chamber pressures



How does a short barrel increase chamber pressure? It should be the same--peak pressure being slightly after ignition and before projectile has traveled more than a fraction of barrel length. As far as I can figure.



but they do add a little to the weapon though as far as looks and charging!!!


Looks aside, I do like an oversized release as long as it's not big enough to bang into my chest.



somewhere along the line I was told that 20in barrels have approx 52,000 PSI threw them and as you get shorter the gas dosent have enough room to expand to 52,000 so there fore is much more...if this is incorrect I would defenatly like to know, Im not a physics master...just what I heard. but I do know for a fact that my short barrels and suppressed weapons have a hell of a lot of gas blow back.
Link Posted: 2/25/2006 9:20:29 PM EDT
Port pressures in carbine lengths are higher and more importantly there is less tube length and cosnequently volume involved so you get more gas more quickly. That's why the carbines have a higher ROF than rifles and have greater perceived recoil, the bolt carrier is being driven back with greater force by the higher pressures.

That's wahy many of the shorty and super shorty direct impingement guns are now beiing fitted with systems designed to effectively reduce this pressure such as by adding an intermediate expansion chamber or by using an adjustable valve.

Link Posted: 2/25/2006 9:23:24 PM EDT

Originally Posted By SIMPLYDYNAMIC:
somewhere along the line I was told that 20in barrels have approx 52,000 PSI threw them and as you get shorter the gas dosent have enough room to expand to 52,000 so there fore is much more...if this is incorrect I would defenatly like to know, Im not a physics master...just what I heard. but I do know for a fact that my short barrels and suppressed weapons have a hell of a lot of gas blow back.



I HAVE studied physics. Impossible. Shorter length restriction REDUCES pressure. Fact. There is NO WAY to increase pressure with a shorter restriction.

More gas through the tube, yes. But I still don't see how that's going to get out of a closed receiver and near your face. Unless you lean over the ejection port.
Link Posted: 2/26/2006 4:53:06 AM EDT
the gas tube directs the gas towards your face to drive the bolt carrier group rearward, the upper reciever is not a seal tight set up and after the bcg goes flying rearward the rest of the gas gets blown rearward as well. what is directly in the path of the gas tube? the charging handle and your face.
Link Posted: 2/26/2006 5:05:12 AM EDT
I relate this option to when I use to shoot my glock. When I used Blazer loads I would leave the range with residue on my face, glasses and hands. The gun would be coated in a fine powder residue. When I shot UMC rounds, the amt of residue was considerably less. From what I have read you can use a specific spray and with the aid of a black light I believe you can detect powder residue on a person who has shot a weapon. The point of this is that no matter what gas block a person has installed there is going to be residue, but will this specific unit decrease it and how much. I understand the other purpose of the unit is to change the size of the charging handle, but if you can decrease blowback gases from your face that would also be nice.
Link Posted: 2/26/2006 5:22:55 AM EDT

Originally Posted By eklikwhoa:
the gas tube directs the gas towards your face to drive the bolt carrier group rearward, the upper reciever is not a seal tight set up and after the bcg goes flying rearward the rest of the gas gets blown rearward as well. what is directly in the path of the gas tube? the charging handle and your face.



The charging handle on all five of my ARS latch securely against the upper receiver. While not an airtight seal, it is certainly a solid blockage against pressurized streams of gas or particles. As soon as the bolt carrier clears the ejection port, gas takes the path of least resistance and ambient receiver pressure drops to equilibrium with atmosphere. I occasionally get a smell of propellant, but never had any particles.

Additionally, if that WERE true, vent holes in the SIDE of the charging handle would possibly relieve a little more pressure, but WOULD NOT magically redirect this stream of gas...unless by making holes we somehow obtain the gas tight seal you note isn't there?

I've used 11.5" military carbines and not had the described problem. Spoke to a SEAL who use suppressors, and he has not had the described problem. I'll keep asking, and I've got an inquiry in with someone who can describe the pressure curve in the barrel and gas tube better than I can.

I can't think of a way to post the relevant equations for cyclic pressure pulses here. I'll see if a aeronautical engineer I know can model it real quick and post a link for the curious. However, the described problem is neither common nor easily described, given the non-cylindrical shape of the plenum involved, and a "solution" to said problem would involve (as was noted upthread) an expansion chamber in the gas tube to moderate the waves, or a change in gas port size.

I'm really trying to visualize a solution involving vents in the charging handle. Said vents would reduce mass and create stress risers that would weaken the charging handle, and would lead at best to a faster drop in receiver ambient pressure to atmospheric ambient. It could reduce the pressure pulse in the immediate volume around the gas block. However, as soon as the gas block (with the bolt carrier) has cleared the front end of the charging handle (which for purposes of the firing cycle is a fixed component), gas will immediately flow into the entire receiver volume and magazine well. Additional holes in the charging handle do not appear to be of particular advantage to this event.

I'm trying to find a practical reason for this device, but so far, I'm coming up with marketing BS.

Looking at PRI's other accessories, I don't see anything of significant use I can't buy cheaper elsewhere or do without.

But your mileage may vary. That's why the pic threads have 400 different variations built on the same receiver.
Link Posted: 2/26/2006 5:35:15 AM EDT
Very well put thank you
Link Posted: 2/27/2006 6:30:56 AM EDT
Feamster talks about the occasional puff you will get, and in rain it fogs your glasses. I can't remember how he did it, but he came up with a cure using some Silicone gaskit material.

Feamster book, and Accuracy speaks two books cover about everything you'd ever want to know.
Link Posted: 2/27/2006 6:43:31 AM EDT

Originally Posted By CKing:
Feamster talks about the occasional puff you will get, and in rain it fogs your glasses. I can't remember how he did it, but he came up with a cure using some Silicone gaskit material.



Someone posted an image of that on THR, and said silicone spray does much the same thing.

I DO like the PRI latch. The one I have protrudes an inch and jabs the chest.
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