Gibbs

It's just a DPMS LR308 Oracle I bought at Cabela's in Grandville, MI. Traded in one of my 6.8 SPC rifles I built for it and thought it was not a bad deal for a new rifle, but also odd that I didn't get any owners manual, box, etc.. just the .308 and a magazine. Found out later it was actually used. VERY little used, but still used. I can only imagine that someone bought it, shot it, found out it kicked, and traded it back into Cabela's (original FFL who owned it). So, nothing special barrel, 1:10 twist 6 groove 16" barrel.

I grew up in rural western Nebraska. In Omaha, there was a society, I think, with the name Ak-Sar-Ben, which is Nebraska spelled backwards. Since I used to shoot some AK type weapons, I just made the first part capitol letters. AKsarben. :) I shave with a straight razor sometimes, and found one with that unique name on it (made in Germany) and restored it from this: To this.... Shaves pretty nice too. Had to loose just a little off the end because of the broken blade, but otherwise pretty good.

Also, on the safety bar switch I drilled a small dimple and filled it with red paint, so that when the safe is on, that dimple is covered. But when in the fire position, the red shows and you can physically feel the dimple even in total darkness. Same thing on the opposite side. The SIG522 has ambidextrous safety switch.

After I got my SIG522 I decided to remove that fake gas block (adjuster) that actually works on the SIG556 and replace it with a laser with remote switch. Got the laser at Walmart for about 30 bucks or so, and I drilled and tapped the side holes 8-32 for set screws. That kept the laser firm and mounted toward the top so that the elevation and windage screws would still be accessible and able to adjust it. Does it work? Raccoon on the porch with the laser dot between the eyes, as well as the possum near the side of the house (same condition at night) would attest to that... but they are not with us anymore. Wherever the dot is, the bullet hits.

I'm not a troll. I'm AKsarben at 68forums, http://68forums.com/forums/showthread.php?50755-Difference-betweeen-5R-like-ARP-and-5R-Polygon-barrels/page2 M4 Carbine forums as AKsarben http://www.m4carbine.net/forum.php, SIG forums http://sigforum.com/eve/forums, and AkSarBen at AR15 forums: http://www.ar15.com/forums/ and, where I probably started with the AKsarben name (AK as in Kalisnikov) was at Saiga Forums. I had a .223 and a .308 Saiga at one time. http://forum.saiga-12.com/index.php?/topic/53559-how-or-could-better-accuracy-be-achivied/?hl=aksarben#entry511695 Picture here of the .223 group and reference to that AKsarben name.

Nope, reference: http://www.michigan.gov/dnr/0,4570,7-153-10366_37141_37706-31579--,00.html with the exception of a pistol with a concealed pistol license. They changed the law defining in Michigan the length of a rifle, like this SIG when folded, etc as a rifle, but before that law was enacted, it was registered and considered a pistol. I was allowed to re-register it as a rifle, but then, if I did that, I would not be allowed to carry it in the trunk with a magazine in it per regualations about carrying rifles in transport. So I stayed with the grandfathered issue that it's a registered pistol and can carry it in the trunk and not worry about the magazine in or out of it. I too, thought about the GSG pistols and even looked at the Kalishnikov .22 rifle over at On Target. Decided against it, under the same things as you all said.. looked kind of cheap and, well... cheap. The SIG caught my eye and I have lucked out and it's been a real dream to shoot and easy to clean. I'll post a separate thread about the mod and will cease hijacking this thread of the modification of a AR style charging handle fix for the .22 for Robocop's wife's rifle. Well? Has it been fixed and shot? How did it all turn out?

NEWS flash! SIG Sauer model 552 is made by SIG Sauer in Exeter, New Hampshire. Says that in my owners manual and just got off the phone with SIG in New Hampshire (603) 772-2302. This is not made by Umarex. In this picture I drilled and tapped threads into the area where the fake adjustable gas regulator was so I could mount a laser in it's place and hold it steady. Magnet sticks to it and it is steel. The body is polymer, like my SIG Sauer SP2022 9mm. Flash hider is threaded 1/2-28 and takes the same flash hider that fits on any .223/5.56. One thing about it, I have shot lots of crappy ammo through it without a hiccup. It even shoots the standard velocity .22 LR ammo I have from CCI. Deadly on raccoons and possum in my yard. Never had any issue with it's side folding and collapsible stock, locks up very solid. One thing you have advantage of Robocop 1051 is you can put another AR-15 upper on your lower and good to go. I am pretty much stuck with just .22 for this little rifle. Incidentally, I had to register this as a pistol in Michigan since it folded to the side and overall length made it too short for State rifle regs, but was ok with Federal. Which was before they changed the law, but, with my Concealed Pistol License, and this registered as a pistol, I can leave a magazine in it and carry in the trunk and get by with it. If it was just a rifle it would be illegal. Odd huh? 8-32 set screws with thread lock.. and left side with the momentary on/off button on the side of the fore grip.

It would be more logical to talk to David Tubb and see if I can get one without any threading. I worked at Boeing back in the later 1970's early 1980s. They had macines. I now work as a wine maker but only have a wood lathe and drill press in my shop (along with band saw) but even that 5/8 - 24 tranlates to 0.625" x 24 pitch thread and David Tubb's brake is 3/4 - 28 or 0.750 x 28 pitch. If it were smaller I could drill, ream, then tap the larger size thread, but don't work going the other way. Not much room on the end of the barrel anyway. Just for fun last night I shot a 3 shot group of one of my hanloads with the flash hider off the end. About a 1.7" inch group. Put the flash hider back on, snug, and the same batch of reloads shot about a 0.543 in group. So even that little bit on the end of the barrel seems to matter.

Looks like a good job of making do a repair. LIke you said, Robocop, the filling in can come at a later date, but should work fine the way it is. I had dabbled with the idea of an AR in a .22 configuration keeping price of ammo down and so on, and sort of leaned toward the SIG 522. Forgive me all, for my weakness, but for what I was looking for, it was right for me. I even put a laser in place of the fake "gas adjuster" on it, and those SIG handguard can take the same rails as the SIG 556 so I can mount a llight on the side for critters at night. How's it shooting now? Wife should be much pleased with the new modification you did.

YEP!! Excellent groups!

And with the new .308 LR308 DPMS

Welcome from a guy from Oshkosh, NE. other sites I'm known as AKsarben. :) Guess I should post a pic..... this is Wiley Coyote that was in the back yard, 335 yards. Shot with the 6.8 SPCII 16" AR Performance rifle with the 1:11.25 twist 5R barrel. All home built. (it's a piston gun too).

That would have been an excuse to get a SIG 522.

Got an email back from David Tubb (really nice guy) about their muzzle brake and if it would work for the .308 AR series of rifles. What he said " Yes you can tune the AR10 barrel like you can with a bolt action. When using our muzzle break and break nut you want a ¾” x 28 TPI muzzle end and will have to drill the hole for the .308 as they are made for the .243 bullet. If there is anything else we can do for you please let us know." Big thing is I really don't want to thread the end of a barrel 3/4 - 28. REALLY fine threads. Looks to me it would make more sense to buy the muzzle break unfinished, with no threads at all and just a pilot hole in the end. I can thread it 5/8-24 then drill out the hole to clear .308 bullets. (I used to be a machinist at Boeing in Seattle) Just makes more sense to tap that end piece to what you want and then you don't even need the special nut as you can buy 5/8-24 jam nut http://www.joeboboutfitters.com/JP_Jam_Nut_5_8x24_925_p/jp-jn.58.925.htm In fact one might find such a jam nut quite handy rather than the crush washer. Nice at times to take off the end of the flash hider just to clean. Local gun store in Kalamazoo, MI (On Target) sell these all the time for that purpose and are currently out of stock on them.

You should see my single shot groups!! :lol: Perhaps I'm chasing a ghost. Back in the 1980's I had a bolt action .223 that when I first got it would not keep 5 bullets on the paper at 100 yards. Boat tails were the best, but even those were inches apart and some even hit the target sideways. Then, I started looking more closely at the end of the muzzle and there was some rifling damage done at the factory. LONG before internet, emails and the like I merely showed it to a gun smithing friend who lived just north of Crawford (NE). Barrel was badly damaged in the crown from the rifling so he chucked it in his lathe, trimmed of about 7/8 inch or so of the barrel and put a target crown on it. After that, using Hornady .223 SP flat bottom bullets 3 bullets hit the same hole. It could repeat time and again and I lost that target some time ago. But I remember a rifle that had had groups that you could not measure center to center as it was one hole. .223 was the minimum for deer hunting and I killed a nice buck the fastest with it next deer season with a shot right at the base of the skull. Dropped like lighting hit him. So now I chase that elusive ghost, a single hole shooter.... But the barrel harmonics were an interesting read and learning piece. I wonder if the actual trimming of that rifle barrel had changed it's nodes and vibration to the point it was such a good shooter? I find the study and information about barrel vibrations, nodes and barrel harmonics very interesting, and wonder if, like that old .223 I had with the cut off barrel, that some of these devices, whether by Browning (BOSS) or what David Tubb has something to do with "tricking" the barrel to think it's loner or shorter than it actually is? The quest to find something that can change how a rifle shoots with different loads and do it consistently was my original thought and idea, but I don't think it really can be done now as each batch of ammo (commercial or home made) will not create the same pressures, and harmonics, nor will a "device" average them out to where they shoot the same groups on paper. Adjustments with scope will have to be made, as well as determine the sweet spot for bullet grain any particular rifle likes and work within those parameters.

I bought a Barrel from Harrison a few years ago. Excellent shooter, and yes, deadly on deer, hogs, and insurgents hiding behind car doors. This is the one I built piece by piece. Lower is Del-Ton stipped lower that I built one evening watching the NE footbal on TV. AR Performance 6.8 SPC II barrel with 5R 1:11.25 twist . I agree with Wash, .... tack driver for sure!

Tom, I'll have to give it a try. Nothing but fun and games, some time. I often forget that not everyone has access to a range within 1 minute of their back door. I'm lucky that I have enough range to test 100 to about 400 yards on my property. I also forget that not everyone handloads. I handload and think it's the normal thing to do, but there are many that never have done it. One of the tnings mentioned by David Tubb in his video as well as what I have recently read elesewhere is the key word "Factory Ammo". People that buy factory and can't get their rifle to shoot "that" particular load they want to shoot, and get frustrated at the group size. However, handloaders like you and my self and plenty on here have the ability to find the bullet we want and vary the powder, charge, seating depth, crimps, etc etc to change the pressure that changes the frequency (barrel harmonics and nodes) that match well wtih that particular barrel. You change the pressure in the brass and you change how the bullet travels down the barrel and how the harmonics affect the bullet the instant it leaves the muzzle. Factory is sort of a "catch all" Rounds are built to be safe, fairly stiff loads, and for some they have really worked out the bugs in making them pretty excellent for a lot of barrels, such as those Match Ammo put out by some well known ammunition manufacturers. One thing I have kept in my head all these years is to never let anything touch the barrel ahead of where it is supported by the stock, or in this case, the gas block. I've known that it makes a difference on where the bullets hit and grouped downrange, but never quite understood exactly why something as simple as resting the barrel on a box, a tree branch, or a sandbag can change how it performs.

Guy doesn't know about the SIG Sauer decocking lever apparently. You don't need the hammer back to fire a round as it works like a revolver in that regard. Thought it was funny when he got done and told about the "locking back" part.

Damn good question!!

Well, he does have a tune-able muzzle brake for the 2000. http://www.davidtubb.com/catalog/view/theme/davidtubb/pdf/product_information/T2K_brake_sheet.pdf It states it has an optional lock nut to tune vibrational nodes. Cost is $119.00 and product description is here: http://www.davidtubb.com/muzzlebrake?search=Brake&description=true Thead is not for a AR .308 though, it is 3/4 - 28 pitch thread. (You'd think I'd learn to spell check before posting) LOL No, I don't think donuts are the answer, nor are rubber rings. What Browning patented and what that one guy has at his site is more on the idea of muzzle devices that are fine threaded for minute changes in the very end of the barrel, even on David Tubb's "Tubb 2000 Custom Muzzle Brake". If you had a 5/8 -24 locknut (thin) one could do something similar with the flash suppressor on the end of the AR 308 rifles. This you tube video of David Tubb talks about tuning your rifle to find a sweet spot with this brake and advancing it out or in a bit for that sweet spot. https://www.youtube.com/watch?v=dqvVHS6T_sM If one were well versed in engineering and metallurgy, you might create harmonics in a rifle barrel and say "Cut this one to 16" + 0.225" and hit the magic spot of node vibration for that particular barrel. But, they are mass produced things (barrels) and as such they are generally cut at 16 1/4" just to make sure it is past the 16" minimum and then the barrel will find it's niche with certain bullets/powder/primer/cases and handloaded to where the ammo is in tune to the barrel rather than the barrel in tune to the ammo.

This has been a great thead, if only for the fact of learning about David Tubb and his site. Thanks 98Z5V for the valuable info and thoughts.

:LOL:

I did stumble across a link kind of on the same thought as above about the movement of the flash suppressor, of a bench rest rifle using a tuner on the end of the barrel. Seems like a lot of scientifc analysis and somewhat interesting views in 3D of how barrels move during firing, according to frequencies. link -> http://www.varmintal.com/aeste.htm

Interesting in my search I found a thread in a "Machinist Forum" site that even they are aware of barrel harmonics and nodes and were discussing "ringing a barrel" to determine where to cut the barrel. http://www.practicalmachinist.com/vb/gunsmithing/ringing-barrel-127452/ I was thinking that one could "tune" a barrel for various handloads that using it might tame the barrel harmonics and vibration a bit. As 98Z5V had pointed out, military snipers use weapons that are not "accurized" with tuners, per se, but I am betting that they do a lot of work with handloads to figures out what works the best in what barrel/rifle. For hand loaders, we are aware of barrel harmonics and what a good load will do for accuracy or lack thereof. Trick is to get the bullet out the barrel at the right time when the barrel has the least amount of any whip/movement at the crown, or at least make sure the load leave the muzzle when the barrel is in the same position of movement shot after shot. I do have a small aluminum clamp in my box of stuff that I think came from a 22 scope or laser set up that has 2 allen head bolts and fits around the .308 barrel. I have a 100 yard range in my back yard (live in the country) which is open 24/7 and I made up some rounds of the same bullet, powder, primer, brass, etc and can take a look at with and without and see if there is some benefit. The ONLY benefit, would be if you could dial the barrel into your bullet weight and small variances in powder charge, seating depth, would be negated. If that can't happen, then it's just another variable that has to be set "right" for it to work as it should. I'll try out some targets and loads,even though this is not a BOSS type of system, it might give the barrel some dampening of sorts in an experiment. Other thought is the actual flash hider on the the end of my barrel. Would it shoot differently without it? I would think it might since it adds weight, and torque on the threads at near the barrel crown. Now I wonder what would happen if the flash suppressor were further out on the barrel by using 2 or 3 crush washers (to keep alignment correct for the non slot end being at the bottom)?

I love to hear opinions and thoughts. I have read and heard about ways to dampen or change the barrel harmonics of rifles. What I understand is that there is a sound wave that travels at the speed of sound through metal when the cartridge is fired. VERY fast, much much faster than through air. In fact it is said that this shock wave hits the end of the barrel, heads back to the breech, then back again to the end of the barrel several times before the bullet has had a chance to exit the muzzle end. I have read that it is important that the shock wave or "harmonics" have not coincided with the exit of the bullet at the muzzle end. I've even Seen a system on one rifle, in video, BOSS (Browning's paten on Ballistic Optimizing Shooting System ) *google search BOSS barrel tuner, and you will see this. You tube video even has a clip on it. What's the opinion of the .308 crowd? There is only a short distance between the gas block and the end of the barrel and was not sure that harmonic dampening can have a benefit in that short distance.