gvnwst
Member
Thats the problem I have with mine, I ordered it with the PRS, but they changed their supplier...
Range results with a new POF SPR (gas piston AR-10 in .308 with 20" barrel).
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rangerruck
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1858; I would say myself, it is too early to tell, on the poa/poi shift. Of course, check your gear for sure, but this could be quite typical, in bbl internal ballistics, as many bbls will do this, some will not, some will not group no matter what, unless they are dirty, some are darn near point of aim forever, first shot out.
so after maybe a few 100 rounds or so shot, try to REPEAT THE PROBLEM!!!
I know, sounds totally wrong, but go ahead and give the rifle a thorough cleaning, especially in the bore, to get out all the copper. then , when you are satisfied, and the bore is clean, and dry, and slightly oiled, let it rest a week.
then, the day before going to shoot it again, take a patch, and get any oil out.
then the next day, go ahead and shoot, just like you did the first day. Try to copy the first day of shooting as much as poss; then see if it shoots the same way; if it gets better, then bully for you, you know it will improve. if it becomes obvious, that it is repeating itself, either you have not corrected a problem, or you have a bbl, that is going to do what it is going to do, period.
so after maybe a few 100 rounds or so shot, try to REPEAT THE PROBLEM!!!
I know, sounds totally wrong, but go ahead and give the rifle a thorough cleaning, especially in the bore, to get out all the copper. then , when you are satisfied, and the bore is clean, and dry, and slightly oiled, let it rest a week.
then, the day before going to shoot it again, take a patch, and get any oil out.
then the next day, go ahead and shoot, just like you did the first day. Try to copy the first day of shooting as much as poss; then see if it shoots the same way; if it gets better, then bully for you, you know it will improve. if it becomes obvious, that it is repeating itself, either you have not corrected a problem, or you have a bbl, that is going to do what it is going to do, period.
rangerruck, thanks for your post ... you've provided some good information there.
I think you nailed it taliv. The mount was most likely moving, but if it was, it's not the mount's fault. The problem is the M.R.R. The cams on the LaRue mount simply don't have enough aluminum rail (length) to bite into. For some reason, POF extended the notches on the M.R.R. rail all the way down.
Every other rail that I've seen only has "half" notches. Compare the photo of the M.R.R. rail to the integral rail on top of my POF in .223. That rail is the "typical" design as is my other AR-15 and neither mounts on those two rifles have moved. The mount on this rifle is being held in place by friction along less than a third of the length of each cam.
I'm not sure what the best solution is at this point. I have some super high aluminum 30mm Mark 4 rings but the scope won't have a quick release option. Another possibility is to find a different handguard that fits the POF. I'll call LaRue this morning to find out if they've encountered this problem before.
taliv said:
I think you nailed it taliv. The mount was most likely moving, but if it was, it's not the mount's fault. The problem is the M.R.R. The cams on the LaRue mount simply don't have enough aluminum rail (length) to bite into. For some reason, POF extended the notches on the M.R.R. rail all the way down.
Every other rail that I've seen only has "half" notches. Compare the photo of the M.R.R. rail to the integral rail on top of my POF in .223. That rail is the "typical" design as is my other AR-15 and neither mounts on those two rifles have moved. The mount on this rifle is being held in place by friction along less than a third of the length of each cam. I'm not sure what the best solution is at this point. I have some super high aluminum 30mm Mark 4 rings but the scope won't have a quick release option. Another possibility is to find a different handguard that fits the POF. I'll call LaRue this morning to find out if they've encountered this problem before.
An update: I took the POF to the range yesterday after mounting the scope in a new GG&G mount ... this one.
http://www.gggaz.com/index.php?id=166&parents=69,128
The GG&G mount has a 2" long steel clamp that engages the rail. It's making contact with six of the "lugs" shown above compared to just two with the LaRue mount. I used feeler gauges to measure the distance from the back of the mount to the front edge of the closest lug on the rail (0.042") and the mount didn't move during 25 rounds. I would like to stress that the issue I had is not LaRue's fault, I have three of their excellent mounts. The problem is due to the design of POF's Modular Railed Receiver (M.R.R.) and the lack of a continuous solid bearing surface below the centerline of the rail (see photo above).
For anyone considering a QD mount for an AR or any other rifle, GG&G are an excellent option to LaRue and others. I'm seriously thinking about ordering a couple of these GG&G mounts for a pair of bolt action rifles once I've run some numbers (weight related).
http://www.gggaz.com/index.php?id=146&parents=69,128
http://www.gggaz.com/index.php?id=166&parents=69,128
The GG&G mount has a 2" long steel clamp that engages the rail. It's making contact with six of the "lugs" shown above compared to just two with the LaRue mount. I used feeler gauges to measure the distance from the back of the mount to the front edge of the closest lug on the rail (0.042") and the mount didn't move during 25 rounds. I would like to stress that the issue I had is not LaRue's fault, I have three of their excellent mounts. The problem is due to the design of POF's Modular Railed Receiver (M.R.R.) and the lack of a continuous solid bearing surface below the centerline of the rail (see photo above).
For anyone considering a QD mount for an AR or any other rifle, GG&G are an excellent option to LaRue and others. I'm seriously thinking about ordering a couple of these GG&G mounts for a pair of bolt action rifles once I've run some numbers (weight related).
http://www.gggaz.com/index.php?id=146&parents=69,128
SpeedAKL
Member
Stunning rifle!
hokeyplyr48
Member
On the POF website it talks about an 18 week minimum for delivery. Was this correct?
And also are there barrels that much more accurate or would building your own upper using a krieger barrel achieve the same results?
And also are there barrels that much more accurate or would building your own upper using a krieger barrel achieve the same results?
hokeyplyr48 said:
My situation was a little different. I called up my local gun shop to ask about ordering a 20" POF SPR and the owner told me that one was arriving that week or early the following week ... talk about a good omen, divine intervention or just good timing.
hokeyplyr48 said:
In theory a Krieger barrel should be more accurate than the POF, but with the gas piston system banging around you might not see a big difference on paper. The POF should be good enough once I get around to doing some serious load development.
gvnwst
Member
Looks like I missed this...yes, I did order it with the PRS, but they changed suppliers to Vltor...I really wished I had the PRS.
Just wondering, how should a Kreiger be more accurate than a Rock Creek? These barrels are right up there, Mike Rock taught Kreiger how to make barrels. Since they are in a AR, you are not going to pretty much any difference, both are literally da stuff when it comes to barrels.
gvnwst said:
My two Krieger barrels are hand lapped to 16 microns and have four lands/grooves and are exceptionally smooth (the bore). The Rock Creek barrels on both of my POFs are not even close to the Kriegers in terms of smoothness (the bore). Running an oiled or dry patch through the Kriegers is a VERY different experience compared to running oiled and dry patches through the RCs. Patches pushed through the RC barrels speed up and slow down along the length and don't feel anywhere near as smooth. It's hard to explain how it feels to push patches through the Krieger barrels ... I can't think of a suitable analogy except to say it's like a running fit between two well machined parts. I'm not saying that RC barrels aren't good ... they're just not as good (IMHO of course), but that's fine with me since I don't expect the same level of accuracy from them. I don't know how many world records have been set with Rock Creek barrels, but Kriegers have set a bunch.
gvnwst
Member
That's odd, my Rock Creek barrels have all been super smooth, just as good as any Kreiger I have played around with. I would be intrested in knowing if POF uses the OEM barrels (button rifled) vs Rock Creek's cut rifled barrels, that might be some of it.
gvnwst said:
I've shot many, many rifles (literally hundreds) that weren't my own, and with the exception of the Lee-Enfield No. 4 Mk 2s that our high school owned, I've never cleaned any of them. My point is, I couldn't tell you anything about the bores in those rifles. I will add that the RC barrels haven't had that many rounds through them yet so they might improve over time as the proprietary bore lining gets polished.
Regardless of all that, I'm happy to own a couple of Krieger and a couple of Rock Creek barrels ... I have no complaints with any of them so let's leave it at that.
I plan on doing some serious load development with the SPR over the next few weeks so hopefully will have some good data to show.
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