Hoot

I'm doing good and Dad bagged a nice doe that is already in the freezer. I could have stuck to my philosophy that whatever God and good fortune send your way, you take it. I had two similar sized does walk up to me on opening morning and I let them pass, figuring it was opening morning and more opportunities would come my way. They wound up being all I saw the entire season, aside from a fawn that emerged seconds after the does walked away, trailing them. My Dad and I are normally meat hunters and take what we're offered. I now have a year to think about that decision. ::) Melt down is a colloquialism for removing all the razor sharp edges from the barrel extension using one of several methods. Fine stones work, but I prefer Cratex grinding burrs in a Dremel. They are rubber with different grades of grit embedded in the rubber and different form factors that remove metal at a very slow rate, leaving a mirror finish behind. I d the same for any surfaces that the cases come in contact with during stripping and extraction, including the underside of the feed lips in my mags. It smooths out the action incredibly well and lends a small degree of feed reliability to the operation. If you're running an upper receiver with no forward assist and occasionally find yourself having to ease a round into battery quietly, the reduction in friction is a big plus. The obvious key is knowing when enough is enough and as slow as the Cratex burrs go, it's easy to gauge with my B&L stereo microscope. Disassemble and reassembly takes longer than the actual time spent removing the sharp edges. I emphasize that no dimensions critical to lockup integrity or strength are impacted. As a reloader, I like my brass to come out minus the "vampire bites", nicks, dings and scratches. Many shooters do this to their firearms or farm it out. There may be a youtube video or two out there on it, not to mention plenty of how-to threads. It's not restricted to just the AR platforms, but usually not necessary in more conventional "hunting" rifle platforms. The look after you are done, resembles a sharpy cast piece of work that had all the rough or sharp edges melted off, hence the term. Google will turn up plenty of examples and images. Hoot

I am so sorry for not replying to your post sooner, but have been busy, first with deer season and second with my 80 yr old Dad visiting from Maryland. Certain things I do with any new AR class of rifle after stripping it down to components to clean and lube include doing a "melt-down" on the barrel extension to save undue wear and tear on my brass and polishing the feed ramp. So I can not say whether it made a difference. Hoot

Terry's experience, which preceeds mine, may well be a testimony to the "diversity" of DPMS tolerances. With my barrel, I can take my stripped bolt and drop a Go gauge into the chamber. Then put the bolt into battery by rotating it firmly pinched between my thumb and index finger. Ditto on factory new brass. That having been said, fired brass exhibits zero shoulder advancement, which probably is not the best setup for the pressure curve. Feeds and extracts fine though. Again, I need to spend more time with it aside from the functional test and a couple of loads I tried last spring. Hoot

Yes Tom. A 24" DPMS 260 Rem barrel to be precise. Fit like a glove. A bit front heavy though given how light the Predator HP is. Some weight in the A2 stock rebalanced it out though. Also yes, a DPMS nut wrench. Seems like this is a well kept secret for some reason. Triple Deuce used one also, but in his case, I believe he kissed the chamber for a little more breathing room. Mine headspaces tight, but not dangerously so. Actually feels like a custom lap to fit job. Perhaps I was lucky though. I guess a lot depends upon how closely DPMS barrels are toleranced from one to the next. I probably should get a dedicated bolt for the 260 instead of sharing the 308 bolt between the two. This summer was a poor one for disposable time and I didn't get as much opportunity to work up both calibers as I would have liked. Now we're sliding into deer season prep, followed by a long, cold, winter up in these parts. I look forward to having back at it next spring though. Hoot

As much as it pained me to do so, I took my 3-pin nut wrench and ground off the center pin. NBD getting two pins to line up. I don't like not having the 3rd pin like every other nut I own uses (thanks a lot RRA), but the two remaining have not shown any undue suffering from having the shoulder the burden. $70.00 for a proprietary nut wrench is extortion. Unavailability is insult to injury. Message received. "We want you to buy entire uppers and not be able to save a little money by discovering that DPMS barrels fit just fine." >:( Hoot

Not sure why the board put my post in this thread instead of the barrel nut wrench one. Erased it here and moved it to the other thread. Very odd. Hoot

Hornady match 308 with the 168gr Amax bullet shoots 5-shot, 100 yard groups around .6 inches, as in one enlarged hole at 100 yards from a benchrest setup and my Predator HP. I have not shot it on a longer range. Hoot

I asked the same question on the RRA Support Forum over at arfcom and Steve assured me they use only anti-seize, which was exactly what I discovered once I got that miserable thing off. Not my choice in anti-seize, but for sure not Loctite. Did you ever see footage of those oil drillers adding a section of shaft. I suspect RRA uses one of those torque units to match up the next gas tube hole. ;) I've had mine on and off a dozen times using what I consider to be "prudent torque" now and I still can not get it "worked in" enough to line up to that original factory setting. Life goes on... Hoot EDIT: A standard Bernzomatic torch will work as well. The finish is very heat tolerant as you would expect parkerizing to be.

You are correct in that I should have prefaced that with from my experience, it was not hard. Quite honestly, it looks harder than it is and though I used but one approach, it is certainly not the only approach. It does hinge upon having some junk lead, a short length of left over EMT conduit, a bernzomatic torch, sandpaper, hacksaw, a vise (or hammer) and some JB Weld. There were times in the earlier years of my life, when I didn't have all of those at my disposal and I should have considered that. Many members of the forum I wrote that on, have different degrees of talent and equipment, but they improvised and pulled it off. Hoot

Put your money to better use and Make Your Own. It's not hard. Just think outside the 9-dots. Hoot

Not to rub salt in all the wounds, but I must be the luckiest RRA owner in recent history. Between here and the RRA specific sub-forum on Arfcom (the only forum I read there), it borders on ridiculous. I'm sorry, but its just plain ridiculous, how long it takes for them to produce deliverable goods. Are they a lot cheaper that way? Anyway, last July, I read about the LAR-8 Predator HP and starting saving my farthings (remember saving) to come up with the MSRP before looking for one. On Thursday, October 13th, the day before the payday when I would have enough, I Googled the make and model name, noting the phone number or visiting the web site of every hit. It didn't take long to realize the expression "Stocking Dealer" is an oxymoron where RRA is concerned. However, on the 4th or 5th site I visited, I found a paintball supplier in Idaho, who said they had it in stock (false claims should be a crime). On Friday, I called to make sure they indeed did have one and ordered it for like 10% less than MSRP. On Tuesday the 18th, my transfer FFL called me to say it arrived. I suspect I should have purchased a few lottery tickets at the same time, but the horse shoe eventually passed out in my stool. Now, I'm back to my unlucky, buy high / sell low, should have been here last week, self ;) The quality of the Predator HP is spot on and though comfortable shooting weather ended shortly after deer season which was a distraction shorty after I got it, it appears to shoot very well. If I hadn't apparently gotten lucky with mine, no way I would wait 60-90+ days for one though. I probably would have either bought an LR-308 off of GB or built an AR-10 from components. For those of you in the "waiting cue", my heart goes out to you. That's my idea of purgatory. Hoot

Thanks for the dimensions. While I got my modded metric FAL mag to run, it is hit or miss at times, so I'll probably order two mags. A shooter and a spare. The web site says "Polymer .308 Mag" or similar. I'm assuming its synonymous with their polymer .243 or 7mm-08 one? Do they kill you on shipping & handling? Hoot

I use one of those Midway, multi-caliber, brush-in-a-blue-box sets. When I got it, about 15 years ago, I tried the Mica powder that came with it, but I wasn't too thrilled with it. I have many kinds of dry lubricant powders I buy for making up my one lubricating concoctions and shot-plating bullets. I use a mix of 600 mesh PTFE and .25 micron HBN. It works great for tight expanders.Those powders are not cheap and I try not to waste any more than I have to. For me, the indicator of sufficient powder is whether the expander shows brass buildup where it contacts the necks. Allowed to go unchecked, that build-up opens the necks up further than the expander intended and brass on brass has a lot of friction, with or without lubricant. If I see a brass ring starting to form on my expander, I stop, clean off the buildup and use more lubricating powder to where it stops. After a get a tray of them done, I blow out the excess powder in each one with a blast of air from my compressor. I don't want that powder getting into my tumbling media when I tumble them the second time, which I do after wiping off the excess Imperial lube, cleaning the primer pockets, trimming to length and de-burring them. Consistent and adequate neck tension is the name of the game for consistent groups. You can get small quantities of PTFE powder or HBN off of *See Site News*, or directly from the manufacturers. I put a teaspoon of HBN in each of my crankcases each oil change. Yes, it really does help the engines and the .25 micron stuff stays in suspension. The oil still has a milky look to it when it comes time to change it. More like coffee with cream actually, but I digress. I've been working off of the 8 ounce jar of PTFE powder for over 10 years now and it's only half used up, so the cost for reloading using it is not too dear. Since I use the HBN for more than resizing, I go through it faster, but it's still about 10 cents worth per 100 resized cases and its a great bullet coating material to boot. That having been said, its overkill as the PTFE powder is all you need. I just like to experiment and came up with using a little bit of each in my resizing powder. If you want to make it go further, you can mix it with your mica. Say 50% mica, 25% PTFE and 25% HBN. Hoot

Now that is illuminating! The changes in the lips make total sense to me, having spent considerable time slowly sliding the 260 cartridges forward and watching how they behave, or misbehave to be exact. Looks like the lip widening done about 1/4 the way back from the front, was done after they are molded. Thanks a bunch. Hoot

This is good stuff! Not to be greedy, but could you also post a looking down inside view, so we can see the followers from above? Looks like the raised part of the followers on the plastic mags is wider than the L1A1 mag. The roll-off of the narrower one seems to contribute to the problems I've seen stripping 260 cartridges. Thanks, Hoot

Could you measure yours and report the average max COL for the group of them? If it's hard to get a caliper in them, pick the longer cartridge you have that will fit and measure it. Thanks, Hoot

Ooh, that is less than I expected they'd want for one and faster turn-around than I would have imagined, with all the horror stories out there. You going to make me a copy cat again Terry, I just know it. It's blue butt cold here right now. Rnage time is a distant thought when you take the dog outside to ee and by the time you get back in, your eyelashes are starting to glue together. Probably won't get much more proofing on the 260 until spring returns. Last year, that was early May, but we may be on track for a mild (by local standards) winter this year. Keeping my fingers crossed. Why didn't you just go with the LR-338 barrel and extension??? Hoot

There is something to be said for "limp shouldering" and full rearward bolt movement. I tend to let the rifle jump around a little on the BR1000 and rear bag. When I was playing with an adjustable gas block, I found if it was adjusted right on the threshold of sufficient gas, not holding it tightly would be the difference between it locking back or not. It was quite repeatable. Death grip = reliable lockback. Slightly tight = no lockback. Solution = a little more gas. Those occasional doubles may also be the result of the trigger follow through combined with a little bumping back and forth. I hold my trigger position and sight picture a good count of 2 to 3 after the shot and never have had it double on me. Happened all the time with a regular single stage. Hoot

Was that directed at me or Spaniky73? Mine stopped doing it after I lapped the bolt face. Hoot No, I'm suggesting that may be the cause. There are certainly other causes for brass shavings in a receiver. That barrel extension is enough to put fear in the hearts of brass manufacturing men itself. That crazy stiff ejector spring is total overkill. FAL magazines...well need I say more? The culprits are endless. ;) Hoot

Those were the first rounds through it as I did a barrel break-in on day one. The residue of a gas impingement system, combined with the spent cases grinding it into the bolt face would probably accomplish the same thing over time, but I reload my brass and use swiping as a troubleshooting aid in determining if I may have gone a few granules past max for a given powder / bullet combination. As such, did not want all my brass bearing the scars it took to efface the burr through a war of attrition. Though visually obvious, the depth of the swipes was so slight as to barely be detectable by feel with your fingernail. It did not have any lasting adverse effect upon reloading them. I eventually spun each of the case heads into a 0000 steel wool pad in the palm of my hand to get rid of the swipes. Now, I can't even tell which ones they were. Still, it was a disquieting initial experience for my first AR 7.62 platform. Hoot

I suspect you are seeing a lesser version of this: My Predator HP had this from the first round on. I broke in the barrel with 7.62 NATO rounds that were pretty tame as 308 loads go, averaging around 2600 fps over the chrony. Every case had a swipe. I approached it as if over-gassing was making the bolt unlock before the case had released from the cylinder. A common solution for this is to install an adjustable gas block. I bought and tried one, but as soon as it was adjusted enough to allow the bolt to start to cycle, I got the same swipes. Besides the ejector swipes on the faces, there was fine brass residue in the bolt face recess. I then increased the buffer weight to further retard the unlocking moment, but to no avail, whether alone or in combination with the adjustable block. It occurred to me that I might be over-thinking the problem. I removed the bolt, disassembled it, chucked a piece of useless, spent, berdan primed, milsurp 7.62 case in the drill press, base down. I then drizzled some 600 grit lapping compound on the bolt face and pressed it up into the slowly rotating case carefully maintaining a square relationship between the two mating surfaces. I retracted the bolt occasionally to freshen up the lapping compound and to inspect the bolt face. Once the parkerizing or whatever treatment they do the bolt with, had effaced and the bolt face was smooth, I cleaned it up, reassembled everything and headed out to the range. It only took a couple of shots to confirm that the swiping had stopped. Several trips later, before it got too cold, utilizing different loads, some more stout, some less, the swiping has never returned. There must have been a sharp edge on the ejector hole, though I could not detect it under the stereo microscope and the lapping got rid of it. There are a number of ways to the same end result. I chose one way. You might consider some process at your disposal, to try, that accomplishes the same thing. Keep in mind that I did not remove much, if any actual metal from the bolt face, other than that which was raised above the flat surface of it. That is important so as not to alter the headspacing detrimentally. I removed the adjustable gas block, but I kept the additional buffer weight as it tamed the recoil impulse a little and the spent brass doesn't seem to get as beat up during extraction. If in doubt go slow and retest frequently. Like my barber used to say, "I can always take more off, but I can't put it back on." Hoot

The ejector spring is so strong on my bolt that it pressed the cases into the sharp edges of the barrel extension lugs during cycling, with enough force as to shave and deeply scratch brass from the cases. Not sure why RRA uses such a powerful ejector spring. I melted off all the sharp outside edges on the lugs and that helped. I searched high and low through my extensive spring stock, but could not fine one with the right dimensions, but less force. I eventually took off a turn or two from the original spring and the combination of those two actions stopped shaving significant amounts of brass off of the cases, not to mention carving them up. My ejected brass now falls next to my shooting position at the range, instead of 5 positions down from me. Since I reload, I normally use a brass catcher, but I took it off for testing. If you're unfamiliar with the term melting off, it is as Jmoto suggested, stoning off the sharp edges. I prefer chucking the barrel in a barrel vise, pulling on my magnifier visor and pulling up a chair. Then, I use grit impregnated rubber polishing points in a rotary tool to slowly, carefully, efface the edges. Rubber polishing points are a godsend. They are not for folks who are patience challenged though. ;) Hoot

I don't think RRA's gas tubes are proprietary. I just set my Predator HP up with a 260 Remington barrel and having removed the stock 308 barrel, block and tube, I laid the tube next to a generic one I purchased for the new barrel. They're the same length, with the same bends. In the case of mine, it is a rifle length tube. I can't comment on shorter gas systems. I'm not into window dressing my rigs and for a reasonable price, the Troy low profile, blackened Stainless Steel gas block I bought from Midway for the 260 bull barrel, fits beautifully under the stock handguard that comes with the rifle. Before it arrived, I was using an aluminum quad-rail block I had laying around for testing. In order for a portion of it to fit in, under the handguard, I had to mill down one picatinny island at the end. Not sure what the sections between the slots on a picatinny are called. The .936 Troy block I got was well made, with a nice, close-tolerance fit. Here what the .750 one looks like. Hoot

This project just got a whole lot more interesting, though a little enigmatic. I've seen my share of manufacturing tolerances going both in my favor and not through my shooting career and I'm wondering if tripledeuce's new DPMS 260 barrel, with it's need to have the chamber "kissed", maybe came down on the short end of the stick? Here's why. I finally got some time to take my new barrel, clean it thoroughly and actually see how it interacted with both my PTG .308 Go gauge and a piece of sized, new, Remington 260 brass. Now keep in mind that my RRA .308 bolt has seen less than 50 rounds, so for all intent and purpose, the lugs are not even close to broke in. The new barrel is just that. Sharp edged and for all intent and purpose, a virgin. Here's where it gets interesting. With the new barrel chucked in a barrel vise on one of my work benches, IE not mounted to the receiver, I can put the Go gauge in with just the bolt, minus the ejector and extractor and hand rotate the bolt into battery. Granted there is zero bolt slop when in battery, but I rotated it just using my thumb and index finger. When I try the same thing with the RRA .308 barrel the bolt originally came with, the degree of resistance to rotation is almost identical. IE, a nice, firm, lockup much like a match grade chamber. Next, I took the fresh piece of new, sized and trimmed 260 brass and coated the shoulder with Dykem layout stain. I placed it in the new 260 chamber and rotated the bolt into battery once again using just my thumb and index finger. It exhibited the same amount of rotational resistance as the Go gauge did. When I carefully removed the case, you could see where the shoulder was engaging the chamber, marked in the Dykem and it was right at the datum point on the shoulder. I cleaned and re-coated the case and chambered it in my bolt action 260 which has a Match chamber cut in it. Upon removal, it had the same marking on the shoulder at the datum point as the new DPMS barrel did. So what are the chances that tripledeuce's new barrel may have been cut with an older reamer, winding up on the slightly short end of the tolerance stick and normally it should have been able to chamber the Go gauge, had it not come from the factory a little tight? I realize that I'm kind of in uncharted waters with regard to what I'm doing, as I haven't found any references on any other forums to someone trying a DPMS barrel in an LAR-8 other than tripledeuce. Has anyone else? Any opinions? I'm thinking I have a nice, close toleranced fitting bolt / barrel combination, that will eventually get a little more smooth with wear and fall right in the sweet spot. Or, am I overlooking something, that you more experienced folks already know about from your own experiences chambering new AR barrels? I've only done this two other times and both were with Remington 700 bolt actions, where I knowingly bought a factory short cut, drop-in barrel that I knew I would have to do a final ream on. I don't want to assume too much on this project as that's where trouble comes from. Obviously, I'd love to not have to rent a reamer and "kiss" the chamber, but if that's what needs doing, I'm certainly up to the task. Please feel free to chime in. I PM'ed tripledeuce the same question and if he doesn't respond here, preferring to do so in the PM, I'll share his opinion, if that's OK with him, in this thread. This could wind up being very good news for us LAR-8 owners who want to try other calibers not currently available through RRA. Even if it winds up that a little touchup work is needed, it's still great news since RRA certainly hasn't chosen to admit the interchangeability of barrels, let alone any of the other more precise parts, with other brands. Thanks, Hoot

What the heck, he we go... If you own a matching set of salad bowls and they all say Cool Whip on the side. You may be a Black Rifle Hoarder! ;) ...next Hoot