Jgun

That .451 IS a pretty gun, and I bet it's got some decent collectore value. May not want to shoot that one TOO much.

Clark also offers a drop in .460 barrel kit. They say that with the comp on the barrel it's not to punishing for the gun. Iv'e always wanted to shoot one of these. http://www.clarkcustomguns.com/rowland.htm

I get the feeling that your doing this because it's your nature, your an inventor, and just as a painter has to paint, your doing this for your own satisfaction, but just as you mention about thinking that HK my have used some of your ideas with their grips, I think that perhaps you should consider keeping some of your progress under wraps at least until you've applied for patents on the innovations that your mentioning. I don't know whether money is no issue to you, but wouldn't it be nice if the profit from one really good idea, allowed you the time and resources to bring your ideas to life on a far larger scale? I think there are many people that have come up with great ideas but didn't get the credit or profit from them because they didn't protect them.

Correct, LRB M25, I called them up this week just to see where my name was on the waiting list for a rear lugged M14S receiver, they told me that they'd had someone back out on the M25. It couldn't have come at a worse time for me financially, but I figured I'd better jump on it. Now I'll be able to put it together according to my schedule/financial situation and not be held up because I'm waiting for the receiver. I don't think I'm likely to be able to pick up my barrel before the beginning of the year.

I guess this makes it official.

I guess I could always use something from Brownell's.

What your describing is exactly what PRI does with their lowpro adjustable gas block, so I don't see why it wouldn't work. They tell you to adjust it and then locktite the set screw in place once you've found the correct adjustment. For added security, I milled a small flat around the screw hole and installed a longer set screw with a nut that I can tighten against the side of the GB to keep the screw from moving, so far it's still there.

From what you've posted I'm reading that your dimension is approx. +.200" from my measurements, is that correct? I don't know what your thoughts are on this idea, but, If you were to take a rifle length gas tube, which only costs $10 so it's not a big deal if it doesn't work, But if you drill a new gas port hole .200" further forward, and then drilled a new, roll pin hole in the gas block so that you can locate the gas tube .200" further back, You should be able to accomplish the same thing as turning the barrel and redrilling the gas port .200" further back. if you do decide to drill the new gas port in the barrel, you'll have to make sure that the new hole doesn't Nick the rifling but is fully in the grooves. If you tried my idea You might have to use some sealer so that the extra hole in the gas tube doesn't allow gas to leak out of the back of the gas block where the gas tube goes in.

I must have confused your build pictures with someone Else's. I could have sworn that there was a DPMS build someone did using a JP barrel. Based on the prices listed at Brownells, and the opinions of all of my 3 gun friends that use JP receiver sets and lightened BCG's, I would be expecting it to be a top quality barrel. I'll be anxious to hear how this one groups for you. Good luck with the build.

These are VERY good looking barrels, Imschur, you've got a JP barrel on one of your other AR's right? How have you found the accuracy to be?

On my DPMS pattern Rock Creek barrel, I'm measuring between, 13.350"and 13.375" from the back face of the barrel extension to the back shoulder that locates the back face of the gas block on the barrel. I'd be inclined to say that the shorter dimension is more accurate. If your going to start turning the barrel down, I'll tell you, the back face of the barrel extension is flush with the inside face of the upper receiver on mine (Kaiser) don't know if it would be the same on a DPMS upper. If it were me, I'd remeasure the existing gas tube to barrel extension dimension and compare it to that .910" I got, along with the present dimension from the barrel extension face to the GB shoulder, You know, it's hard to put the material back on once you turned it off and if you take too much and the gas tube is too deep into the receiver you may run into problems.

Fishco, Don't know if you've already started cutting, but if not, perhaps these measurements will help you to determine if in fact that's what you need to do. I measured the distance that the gas tube protrudes past the back face of the barrel extension. (which is what you will be changing if you remove the material to move the gas block back). On the Armalite pattern (Armalite extension and bolt) .308 carbine gas system gun, the dimension from the end of the gas tube to the face of the barrel extension is 1.035" and on the DPMS pattern, (DPMS extension and bolt) rifle length gas system gun, the dimension from the end of the gas tube to the face of the barrel extension is .910" I also measured a rifle length gas tube that I bought from Fulton, for a DPMS pettern rifle length .308 build I'm doing, and the OAL is 15.156" (that's OAL, not to the gas port hole in the gas tube). Let me know if these measurements are of any help or if some others would be useful. If your gas tube is in fact mislocated, you should be able to tell by seeing if it's way off that .910" measurement.

Fishco, Before you irreversibly alter any parts, let me ask you. Do you have a .308 AR of any pattern that functions? If so, what gas system length is it? Bear with me here if I don't go back to review your previous posts. What is the gas system length You are trying to install? It's DPMS pattern, correct? I think I have a couple of gas blocks and gas tubes on hand. I have an Armalite pattern carbine length gas system gun on hand, along with my DPMS pattern, rifle length gas system rifle (my Kaiser). Is there any way that I can give you measurements from any of the above that will allow you to determine if your barrel is in fact out of spec?

I posted earlier that I have read that the Armalite barrels GB location is approx. .250 plus that of the DPMS. Is there any possibility that you have an Armalite pattern AR barrel? If this were hypothetically true, do you think that a slightly longer gas tube might solve the cycling issues you've described?

This is a topic that I wish was definitively addressed somewhere. I wish there were a chart that covered this. If there is, I've never seen it. What I have found from reading, and my own builds, is that, based on my purchases of Noveske barrels, what they refer to as a .308 carbine length gas system, uses the same length gas tube as the 5.56 barrels that they sell as a midlength gas system. So does that mean that a 5.56 carbine length gas system would use the same gas tube as a .308 pistol length system? I also have read that the Armalite .308 rifle length gas system puts the gas block approx .250" further forward than the rifle length gas system for a DPMS .308. I don't know if they use a proprietary gas tube or make up the length difference in the gas block. I guess this is just one more place where the lack of a mil spec for the large platform AR's makes things confusing sometimes. Does anyone know how many different length gas tubes there are commercially available? What about these SBR barrels, do they make proprietary gas tubes for them? I also have ordered rifle length gas tubes that were straight with no bends in them, while others that I've ordered have had bends made during manufacture. I'm not sure if that is just a manufacturer preference or if they sell gas tubes specifically designed for bull and lightweight barrels that have different gas blocks. It always appeared to me as though the .750 ID gas block oriented the gas tube in the same place in relation to the bore centerline as the .936" ID one does?

I think it's all a plot by 3M to get rid of the competition so that they have the pot scrubbing market all to themselves with their Scotchbrite product (which has no application as far as I know in suppressors).

Not sure why that is, When I click on the link I posted it takes me right to the article. Could another member try the link and let me know if you get there ?

It sure sounds as though there's an awful lot of bureaucratic BS to deal with to own suppressors !!!!! http://www.thetruthaboutguns.com/2011/11/foghorn/atf-classifies-pot-scrubbers-as-silencers-makes-possession-illegal/

Sorry to say, but I have no barrels on hand at this time. I would think that any brand DPMS pattern .308 AR barrel of the same gas system length as yours should be able to give you the pertinent dimensions you need to compare to the barrels in your possesion.

Drew, Is that the same as Silencertalk.com ? Thats the one I usually go to when I'm feeling the need for some silencer envy.

this might be of interest to some of you http://www.botachtactical.com/fazearbakit.html

My home was burglarized many years ago. When the police came to take the report, I asked why they weren't taking any fingerprints, (I guess I watch too many cop shows). They told me that my burglary was low priority because no one was home, no one was hurt and no guns were stolen. They told me to file an insurance claim. I realize that the Police have to focus more of their resources on violent crime than non violent, and that they must respond more quickly to a report of a person with a gun, or shots fired than to a report of a stolen car, but I think that there is something wrong when I'm supposed to wait for someone that comes to my home with criminal intent, to actually enter the house before I'm legally allowed to use deadly force (gun) to protect my possesions. I think that the criminal justice system is defective, if the rights of a person who initiates a criminal act by entering my property with the intent to steal from me (or worse) are considered before my own. After all, I didn't come to his house to shoot him, he came to mine to do, I don't know what. I think that I should have the legal right to use whatever force I deem necessary to protect my home, possesions, and family. Sorry for the rant.

Very clever, I guess that's whats known as working within the framework of society. I saw the other post about the guy that tried to defend his home himself and was shot by the police. I guess in these tough economic times the authorities don't have the resources to protect citizens or their property anymore, but thank god they still have the resources to arrive quickly to arrest us when we choose to take personal responsibility for the defense/protection of ourselves, our families, and our homes/possesions.

Of course with the PRI, if you were to mistakenly put it on backwards, and you mounted the gas block against the shoulder on the barrel, the gas port in the barrel wouldn't line up with the hole in the gas block anyway, so you'd have a single shot rifle that wouldn't cycle at all.

Fishco, Based on the parts you've swapped out, and the fact that the problem remains, I'd be guessing that it must be somewhere in the parts that your not changing. You said that you tried different barrels, right, so it's not your barrel extension. I'm assuming that you've swapped gas blocks and tubes along with those barrels, if not, they can't be ruled out as the cause. I haven't used a DPMS gas block, but a PRI low pro could theoreticaly be installed backward, but that would locate your gas tube too deep into the upper not too shallow as you describe so I doubt thats the problem, The barrel nut should have no effect on the gas tube location. when the carrier comes forward the bolt seats against the barrel extension, so the dimensional relation of the back of the barrel extension to the back of the gas tube is something I would check. You say you have other DPMS .308 ARs. Can you check that measurement and compare it to guns that you know work? If the measurement is the same your problem is not caused by the gas tube being mislocated.