New (older) Guy Checking In

[Hoot]

Greetings folks. In browsing for AR 7.62 platform forums, I noticed this one had more activity than some of the others, so the community here must be more engaged.

Having burned out trying to work up accurate loads for my .300 OSSM (WSSM) AR15 upper, I sold it and and put the money towards a more conventional .308 AR rifle. Unfortunately (not totally) I misread an article in the July Shooting Times about the LAR-8 Predator HP. It gave me the impression that the upper and magazine combination would allow longer COLs than 2.80, which appealed to me in the interest of loading rounds with high BC bullets and not having to sacrifice either powder capacity or bury the ogive beneath the case mouth. Also, if I chose, I could load them long enough to be at the lands. I read wrong. When my LAR-8 arrived, it came with a new L1A1 FAL magazine that accepts rounds up to 2.82 COL. Certainly not the .5 inch increase I misunderstood it to afford.

There were other positive attributes that drove my decision and the promise of other caliber uppers besides the .243 and 7mm-08 currently offered. Given the rise in popularity of 6.5mm (.284) caliber cartridges, I don't understand why RRA did not come out of the chute with either a .260 Remington or 6.5 Creedmoor upper. I have a .260 Remington tack driving bolt action already. Hopefully, they will in the future. Having since shot a friends .260 DPMS, I am feeling a slight amount of buyer's remorse though. Ditto on another associate's .338 Federal. Hopefully, this model does not become an orphan and RRA gets creative in their future upper caliber selections.

The rifle is a class act nevertheless. Fit and finish are excellent. After totally disassembling it other than pulling the handguard and barrel (that's another story) and giving it a thorough cleaning. Lubed it. Reassembled it and took it off to the range for some familiarization and break-in using some LC XM-80. I've owned some .308 battle rifles, including an Izzy FAL, M-14S, G3 and converted M1 Garand in my time. The LAR-8 PHP, right out of the box shot the best 100 yard groups with XM-80 of all of them, averaging about 1.5 MOA off of my benchrest setup. Feed and Extraction were 100% and it really throws the brass a long way when I took off my catcher. The bolt has an incredibly strong ejector spring. It did however, leave crescent ejector swipes on every case head. I don't care for that as that's one of my checks for reloads that are approaching too hot. I approached the problem as one of being over-gassed. I increased my buffer weight from 4.6 ounces to 6.0 with no change. I added a PRI adjustable gas block, adjusting it across the spectrum, again with no change. I then went lower tech and simply polished the bolt face just enough to remove the phosphating and hopefully any burrs and that did the trick. I went back to the factory gas block, but left the additional buffer weight in as it tamed the cycling significantly, not beating up the spent cases as much. Still need to get a slightly softer ejector spring though.

For my first reloading attempt, I chose to load up some Hornady 168gr Amax ahead of 41.7gr AR-Comp powder, from the ATK web site, since that powder is not chacterized in QuickLoad yet. For an element of variability, I tried that load with four different primers to see what it preferred.

Here's the resultant performance:

And the resultant 5-shot 100 yard groups:

I was surprised to get the best group from the cheapest primers.

The comfortable weather shooting season is over for the most part, but I hope to get many days of enjoyment experimenting with other loads when spring arrives up here next April/May.

WRT the handguard. I like running brakes on my rifles, for reacquisition of target and for all day range sessions. Unfortunately, RRA chose not to thread the muzzle and one of my first tasks was to remove the barrel and send it out for threading. I bought the receiver block and the recommended heavy duty strap wrench, but could not get the handguard to budge. Having now had two different gunsmiths decline threading the barrel when they could not get the handguard loose in their shops and fearing damage to the receiver if they used more force, I am getting ready to send it back to RRA to have them loosen it. Whatever gorilla put it on at the factory, had no regard for torque specs, though the factory rep assured me "They always use anti-seize" when installing them. If something gets trashed, let it be on their nickel. There is no excuse for using that kind of force installing a handguard. If the gas tube hole doesn't align at proper torque, that's what handguard shim washers are for.  >:(

Anyway, kind of a long initial thread, but I'm long-winded anyway. Rest assured, I'll share my joys and sorrows as I get to know this rifle. Look for plenty of range reports come this spring. In the mean time, I'll be looking for a source for an aftermarket .260 Rem, .300 SAUM, or .338 Fed barrel if RRA does not come out with one or more in the future. I do love experimenting with the fringe calibers in ARs.

Hoot

[imschur]

Great entrance Hoot, nice post and groups  <thumbsup>

[Hoot]

Great entrance Hoot, nice post and groups  <thumbsup>

Thanks imchur. I am still reading around the other sub-forums, but it looks like a you run a decent group of members. I'm big on civility and open-minded forums, with a minimum of trash talk. Life's too short...

I thought I uploaded my hallmark avatar's URL, but I'm not seeing it in my post. Perhaps I did something wrong as even though it seemed to accept it, the next refresh showed "no avatar" selected. Is there a minimum post for your avatar to show? What is the dimensional pixel limt? Perhaps mine was too large, though I tried two different sizes.

Hoot

EDIT: Guess I could use a dose of patience. My avatar suddenly showed up while reading another sub-forum.

H-

[unforgiven]

Hello brother Hoot another experienced gunner welcome there are plenty of them here.Did you ask RRA why they cranked down the hardware?you are right to let them fight with it.Did you tell them what options you would like to see on there products being I believe to be a customer driven market.Since the barrel& nut assy is proprietary can't uppers be swapped while maintaining RRA lower?Is it possible to launch a 7.62X63 or .416 rigby through a stoner design?Can we hurl a bigger chunk of lead faster longer without getting into .50 cal?You shot some outstanding groups why low left?Didn't mean to grill you right out the box,as I'm as dumb as they come[by the way I have RRA products].Shoot on bro. ;D

[edgecrusher]

welcome hoot, nice shooting.

[planeflyer21]

Howdy Hoot!

That is a good introduction!  Gonna take out my RRA Operator in the morning, run some surplus and some hunting ammo through it.

Jon

[Robocop1051]

Hoot, welcome to our playground... I hope we have something to offer you. From the looks of your first post, you've been around the block once or twice already though.

Without trying to thread-jack here... I think the only platform that accepts the longer cartridges are those that use the G3 magazines. While that platform isn't my personal choice, I really do have a fondness for the Fidelis Arms receivers. If for no other reason than the fact they are trying to build a 12 guage upper!

[Hoot]

...snip...You shot some outstanding groups why low left?...snip

I zeroed the scope using the aforementioned XM-80 and that was where the 168's flew. In the interest of not changing any more variables than I had to, I let the rounds hit where they chose. I was more interested in the groups than scope zero. Also, I shot all 20 in a round robin to reduce the chance of one lucky 5-shot group skewing the results. The CCI 200 group was comprised of shots #4, 8, 12, 16 and 20. I ran right up to deer opener fiddling with it, so I did not zero it out and take it this year. Main deer upper for close in is my 450 Bushmaster. Most of where I hunt in northern MN is thick as the hair on a dog's back. Then there are occasional sloughs, marshes, or long stretches of old logging trails. For those scenarios and as my backup caliber, my other upper was a 6.5 Grendel. IMHO, the most accurate out-of-the-box, AR15 platform caliber made. My worst 100 yard 5-shot group with it has been thumbnail sized, with pinky nail sized being common. Makes a shooter like myself look like Vasseli Zaitsev  ;)

Hoot

[unforgiven]

Thanks for the reply bro your worst day shooting would still probably be better than my best day,I shoot whatever .308/7.62 I can get my hands on nothing fancy,55-62 gr. in 5.56.Will look forward to your posts I sure I will learn alot.Shoot on bro.

[Hoot]

Hoot, welcome to our playground... I hope we have something to offer you. From the looks of your first post, you've been around the block once or twice already though.

Without trying to thread-jack here... I think the only platform that accepts the longer cartridges are those that use the G3 magazines. While that platform isn't my personal choice, I really do have a fondness for the Fidelis Arms receivers. If for no other reason than the fact they are trying to build a 12 guage upper!

Thanks for the link. Though I had heard of a 7.62 AR platform based upon the G3 magazine, I had not known the particulars. It did make me curious enough to go measure the one G3 mag I had left from back when I owned mine. Based upon that mag, it will tolerate up to about 2.875 COL, which though not earth shattering, is an improvement worth noting. Those 168gr Amax' hit the lands at 2.89.

I mentioned the nice fitting L1A1 mag that came with my LAR-8 allowing 2.82 COL. I still have a metric FAL mag from back when I had my Izzy and surprisingly, it edges out the L1A1, coming in at 2.84 COL. Not enough to get excited about though. With the shorter leade and throat afforded by the chamber design that RRA uses in the LAR-8 PHP, I suspect magazine COL limitation will not play such a key role as it did with my .300 OSSM (WSSM) I recently parted with.

Olympic utilizes a much longer leade and throat in that chamber and long ogive bullets have quite a jump from the magazine limited 2.26 COL to where they engaged the lands around 2.46 to 2.56. There's a good example of how risk mitigation lawyers can screw up a design. Had they used a shorter leade and throat, I believe more bullets would have shot accurately from it. By accurately, I mean MOA or less.

I still have a half inch thick stack of targets from different bullets that perform admirably in other .30 caliber cartridges that shot 1 1/2 to 2 1/2 inch 5-shot groups at 100 yards in the .300 OSSM. That's an example to me of not accurately. That's why despite it producing some awesome velocity, IE 150gr Speer HotCor up to 3015fps, it is no longer my upper.

Though the .308 gives up some umph to the .300 OSSM, I'll take the improved accuracy any day. Add to that, the fact that only Hunting Shack Munitions makes one (150gr) commercial ammunition loading for that caliber and it running $2.50 per round (shipped), the non reloading shooter is seriously hampered in terms of ammunition. Certainly not a rifle to take out plinking, unless you have deep pockets.  ;)

Hoot

[Hoot]

Good News!

I'm a tenacious person WRT problem solving, in that I have a hard time knowing when to throw in the towel. Some times it leads to success through perseverance and some times it leads to a lot of lost time and only then throwing in the towel. I've been a little obsessed with getting this LAR-8 barrel off, so I could send it out to have the muzzle threaded and I've already written of that challenge yatta yatta...  ::)

A local, fellow, amateur smith and I were talking this morning about it and he had an idea of employing a second Rigid strap wrench on the opposing side of the handguard to bias it more to the centerline of rotation, when applying pressure. The basis being the nature of aluminum on aluminum wanting to seize under pressure and whether applying the strap wrench to just one side was perhaps offsetting the stress to the other side and precipitating that binding. Even in the presence of alleged anti-seize.

He too has worked on his share of AR platforms both for himself and others and has the exact same model (#2) of Rigid strap wrench as I have. So he came over and we chucked the receiver in the fixture. He got on one side and I on the opposing side with our wrenches. Also, having tested the anodizing in an inconspicuous area for heat tolerance already, I applied heat to the handguard directly over where the threads were. On the count of three, we both gave it a yank and sure as you bet, it broke free.

No barrel nut. Just the handguard holds the barrel in, but then I've seen that on other ARs with an FFT from time to time. In RRA's defense, they did use anti-seize on the threads. Looked like the standard Zinc and Vaseline stuff you can buy. I prefer Jetlube KOPR Kote myself and that's what it's going back on with, but to each, his own.

Score one for the good guys.  <thumbsup>

Now, I've got to find the contact info for the fellow up north of me who threads muzzles. Back to work tomorrow...  :(

Hoot

[unforgiven]

I must have missed it but what type of barrel was it ? My 20" has a Smith Vortex.I like the approach to freeing up handguard was it the aluminum one with rails?Shoot on bro. <thumbsup>

[planeflyer21]

Hoot, after reading all the disclaimers on RRA's website, I'd be interested to know what the pitch and type of those barrel threads is exactly.

It would be nice to know if it is just a big legal disclaimer from RRA.

Jon

[Hoot]

The Model of my LAR-8 is the Predator HP. The Barrel is 20" SS with an odd profile not like any mil profile I've ever seen. The barrel is marked 3-223S/

The receiver thread appears to be 1 1/2-18TPI. There are 8 threads, so an FFT or barrel nut must be deep enough to allow 8 turns and a little length past where the threads end to where the receiver body occurs for a total depth of .625. There is no barrel nut. The FFT body is the barrel nut. It's late, but I will try to get some images up tomorrow.

Hoot

EDIT: Did some googling and the 223S means "Stainless  NM (rifle) unthreaded muzzle". No idea what the 3- or the / means

[Hoot]

Here are images that apply to the discussion:

Barrel Profile

Barrel / Receiver Junction

FFT Threads

Hoot

[Jgun]

If your RRA is in fact threaded 1.5"-18 it is a proprietary thread. The Armalite and DPMS pattern uppers both have 1.437 barrel nut threads, 16 and 18 pitch repectively.

[planeflyer21]

Thanks Hoot and Jgun!

Seems like someone could make a few extra dollars with some aftermarket accessories with all these different threads.

Hhmmmm....

Jon

[Hoot]

If your RRA is in fact threaded 1.5"-18 it is a proprietary thread. The Armalite and DPMS pattern uppers both have 1.437 barrel nut threads, 16 and 18 pitch repectively.

Just to be clear. If you mic the maximum thread dimension on the receiver, it measures 1.426 inches. That is within the range of values yielded by a 1-1/2 - 18 die which varies depending upon the Class of thread and the die manufacturer. Your 1.437 inches is also within the range of values yielded by a 1-1/2 - 18 die. There's that much thread variation in dies. For example, I have some 5/16-24 stainless screws that mic at .3045, not .3125. Still, they're called 5/16-24.

Hoot

[Tripledeuce]

I miked things out, and installed a dpms .260 rem barrel on my rr lar8.

Other than getting enough gas through to function,,,it shoots great!

  Respectfully

  Terry

[Hoot]

Well, my barrel came back from having the muzzle threaded and the brake indexed and I must say, Jim Pixley did a fantastic job on it. He will get more of my business when I need that kind of work done.

I doped the threads with Kopr Kote antiseize and got it to index on a gas tube hole while applying the proper range of torque. While getting a hole to index at the proper torque was my goal, I arrived at that point one hole earlier than the factory did and my sling stud is now 15 degrees off center. Fortunately, I don't use a bipod, so it's not a show stopper, but short of sourcing and purchasing the appropriate shim washer(s), it will look odd to the observant bystander at the range. My Safari Sling will not mind when I take it hunting though. It's actually supposed to get above freezing tomorrow, so perhaps I'll load up a few known-good loads and take it to the range for a short proofing session.

Hoot