Jgun

As I stated in my last post, I'm not familiar with your specific setup, but I'm thinking that your permanently fixed flash hider is going to be a problem. The 3 most common od's for the GB mounting area of the AR barrels is .750", .875", and .936" unless yours is .936" (doubtfull) and your FH is smaller than that, it would have to be removed to change the GB. You should take a look at the GB's of Bob at Firebird Precision. If memory serves me correctly, I think he may have a two piece GB, but I have no idea whether it will fit under the Apex FFtube or not.

I have the Apex FF tube on my 300 (AR 15 platform) and used the PRI low pro adjustable. The Vltor low pro would also clear, I believe that PRI has that type of GB to fit most any GB pad OD. I'm not familiar with the set up of your gun, but standard rule of thumb is that if your going to cover the GB with the FF tube, you'll need to use something like the ones I've mentioned. If, on the other hand, your gas block will be in front of the handguard, you should be able to use whatever one you like as long as it has the right bore ID to match your barrel OD and there are no clearance issues with the gas tube and the barrel OD behind the gas block.

I'm really liking that M1A. Thats in the Troy stock, right? Can you tell me what it weighs? is it sub MOA?

It certainly is reassuring to know that people are making the PF with this rd. I have everything that rsilvers lists for the load, except that powder. I just placed an order on the Fourth for some more of the LIL GUN, and I ordered some Vihtavuori N110. I just did a quick check, and it looks like the 2.245" COL will fit in the Pmag, but just barely. Hopefully, I won't have to make any mods to the center rib. I am hoping that I may be able to make it with the 155's because they might not drop quite as much as the 175 SMK's. Another thing that may help me is that my barrel is 18" and I see that all the data was compiled using a 16" so I could possibly see a little more MV from mine, but this is certainly good news. Up till now,all I've gotten from people is that "Yeah, you can make major", but when I ask for a load it's always "my buddy did it" or some other excuse. Now all I have to do is make the time to load those test rds.

sent you an email wickedfish

I spoke to Krieger today, The person I spoke to was very helpful and patient with my questions. What I came away with from the conversation, was that Krieger in their testing had found no advantage or improvement in accuracy between the 5R rifling which was developed by Obermeyer, and their 4R rifling. I think that it's not so much a matter of whether the barrel is 4R or 5R rifled as much as it is a matter how well the rifling is executed. I think that what your paying for from Krieger is their attention to detail more than the particular type of rifling. I'm guessing that, with their reputation as makers of some of the best barrels available, if there was a clear cut measurable accuracy advantage from 5R rifling, they would offer it. That being said, you can get 5R barrels for the M1A/M14 if you want, just not from Krieger. So I guess that when you buy your barrel from a reputable company your more likely to be getting an accurate barrel.

Thanks for your research on my behalf Robocop. Maybe the point that you made about the M1A not having a freefloat barrel could have something to do with it, but aren't AR's with standard handguards non free float? The set up that I am going with will have a stock that doesn't glass bed the action, it is supposed to be close tolerance machined for a snug fit, with the action bolted in to it. At the mfg's reccommendation I ordered the optional barrel tensioner, which is supposed to improve the accuracy of the non free floated barrel. I'm just guessing here, but was thinking that maybe the reason for the 4 groove barrels is because that is what they used when the guns were first mfg'd in the 50's. Of course, I'm sure that someone has tried out other types of rifling in the past 50 years, and if it really showed a marked improvement in accuracy, everyone would be shooting the other barrel type. I believe your right about the 4R rifling having less resistance than 5R, and that should equate to lower pressures. I was told by one of my barrel makers that the longer rifling 1/12 vs 1/10 gives slightly lower pressures. I plan to give Krieger a call this week, and if I'm lucky enough to get someone on the phone that's willing to take the time to answer this, I'll post the information I receive.

I intend to research this further but this is my first stop. I figure I'll see if the experts over here can shed some light on this. All of my AR's (I think) have 5 groove rifling in their barrels, even though most came from different manufacturers (except two Noveske barrels) I've been looking at M1A barrels from Krieger and others, and notice that many have 4 groove rifling. Now we're talking about gas guns of the same caliber (.308) so I'm trying to find out why they are so popular for the M1A's and not the others. I would think that you'd get better accuracy from a 5 groove barrel than from a 4 groove.

The problem of rapid mag changes had never even occurred to me. I'm thinking that it must be problematic on most, if not all bullpup designs, considering that the mag is going to be located behind your trigger hand. I've never even tried a rapid mag change with a conventional M1A, but have heard that because of the AK like mag release location it is not as efficient as on the AR platform. I'm not sure if that alone would be a deal breaker for me, but the transfer bar to operate the trigger might be. I've shot a few different guns with an additional link to relocate the trigger ( the as imported Saiga 12 ga comes to mind) and I don't recall ever shooting one that had a decent trigger, even by combat standards. Although I've never tried the AUG or FN FS2000.

survivalshop, when the legs are folded up under the gun, are the pretty secure, or do they wobble around?

At this point I'm still interested in finding out if I can achieve the 320 power factor from this rd out of my 18" barrel, without seeing signs of excessive pressure. I plan to load the rds that I mentioned, in small amounts (5-10) to see if it's even possible. If I'm able to get loads that will make it, I will then start getting serious about the accuracy. I had actually gotten almost 2,100 fps out of the 145's the first time around. If I can get that fps with the 155's, that would equate to major power factor. I have been led to understand that this cartridge is not going to shoot flat like a .223 at 200 yds, And it is my understanding that the heavier the bullet the more it will drop at longer range. I'm thinking that the Lapua 155's I have may be my best bet. We shall see.

I thought that when you turn the gas adjustment in all the way on the JP block, it shuts off the gas completely and makes the gun a single shot? If that's correct and your's is cycling with it all the way closed, wouldn't that indicate something wrong with the GB (maybe not threaded deep enough? Can you adjust your gas impulse down low enough that the gun doesn't cycle?

I just ordered several pounds of powder, and 4K primers from Powder Valley. They're running a 10% off everything you order July 4th special until midnight tonight.

Any of you guys ever tried the varsa pod bi pods?

As far as I know, Titanium also doesn't work well in applications where there is friction unless it is coated with something. So that would add even more to the cost of a titanium receiver. I think that it would be possible to get one down to around 9lbs if you could get a carbon wrapped barrel and used one of McCann's 1.5 lb carbon fiber stocks. But I wouldn't expect to see Magpul offering M14 mags any time soon.

This may be a long one. In my effort to come up with the ideal load for my 300 I picked up one of those Hornady cartridge overall length gauges since I read here that loading your rds with the bullet close to the lead for the rifling contributes to accuracy. I had originally thought that the limiting factor to accomplishing this would be the space in the pmag. What I found was that the chamber to my 300 barrel would allow me to load the 145 gr bullets that I used for my first test loads, .125" longer than the 2.1" OAL of the first batch. Unfortunately, the bullets themselves prevent that, I would only feel comfortable going maybe + .03" longer than the last batch because I feel that there really isn't enough case purchase on the bullet. Thankfully, due to many generous people, I have several other types,weights of bullets to test. The first bullet next to the loaded rd is the 145 that I used for those test loads, the next one is a 155 Lapua, and the green tipped one is a 180 gr of unknown brand. The 155 and 180 both look promising, the only thing that concerns me is that in order to set the col properly in relation to the lead, I will have to seat them around .100" deeper into the case. As long as there is no problem with powder capacity in the case, they may work the best for me. If I can get them loaded this week, I'll just need to find time to get out to the range to chrono them.

Your point on the hearing damage is well taken. I just shot my first 3 gun match using my Mega .308 carbine, instead of a .223 gun. Now, I've been shooting open pistol for a while, and everyone knows that the open guns with the comps are much louder than the limited and production guns without, but I've been able to get by with single hearing protection to shoot up till now. But when I came home from the match after shooting a .308 AR carbine, My ears were ringing, I can just imagine how much worse it must be with a bullpup. I guess I'll have to double up with plugs and earmuffs in the future, if I want to use the .308 for matches.

I won't argue with you that, there is no way for a gun to be the best for every role. If that was so, we'd have many different Mfgs making basically the same configuration of gun, because it was so clearly superior than all other designs. I also know that, speaking for myself, and probably others, we like having something unique that no one else has, sometimes people go to great lengths to achieve that goal, even at the expense of practicality. Now I'm not in combat so I don't have real world experience to draw from, but it would certainly seem to me that a small compact .308 rifle, that doesn't lose the long range ballistic value of the .308 cartridge the way a .308 SBR does, would be a very useful thing, Now I don't think something like this is going to compete with a long heavy sniper type 7.62, any more than a Sage EBR stocked M14 would, But I'm thinking that a gun like this might serve multiple battle field roles better than something like a .45 SMG, even if the 7.62 rd would be punishing on the shooter, to shoot in an enclosed space, as I assume it would be.

When I started my first .308 AR build, I asked around, (didn't know about this forum then) and the people I spoke to told me there were some problems with the Armalite mags, as well as being more expensive than the Magpuls. So, based on my good experience with the AR 15 Pmags, I went that route. Prior to using the AR 15 Pmags, I had always preferred metal mags for all my guns. Once I got used to the Magpuls I kind of came around about the whole idea of using plastic mags. Since that time I have heard many more opinions on the Pmags, Some positive, others not. It would seem that the 5.56 mags have a better track record than the 7.62. I have been lucky in that they have functioned 100% in all of my .308 AR's, but I have come to view them as somewhat disposable. I believe (without any proof to date) that they will wear our sooner than metal mags. In some ways that might be not such a bad thing, I'm thinking that the plastic being softer than the mag well or mag catch, is likely to wear quicker than the receiver. I figure it's easier to replace mags than the lower receiver. Besides that, by going SR25/DPMS compatible, I have the option of the plastic Magpuls or the metal DPMS or KAC mags. Another thing which may or may not be true, is that it seems that there are more aftermarket parts available in the DPMS SR 25 pattern than the Armalite, so you have more options for parts selection when doing a build.

I think you SHOULD post a picture of it. You'll be doing your part to "plant the seed" for others on the forum. Someone will see what you've done, and will be inspired to start their own build.

So, what are your plans with regards to the upper/barrel/handguard,stock, if light weight is your goal? One of the things that I found while building my .308 AR's was that there is a difference in weight between the different upper/lower sets. Some of the billet sets are several oz. heavier than the AR-10 set. The other components all become a matter of personal preference/planned purpose, and your budget. Since you've started your build with a lightweight lower, you'll just have to see how far your willing to go to make that lightweight carbine. Good luck.

Was looking at this recently, I like he concept, but I'm not sure I'd be willing to drop over $1200 on one without handling it and feeling the trigger pull for myself. The website says it adds 1.5 lbs to a stock M14. don't know the weight of one of those but I bet it's got to be heavier than my Mega carbine, but probably more compact as well. I spoke to the mfg, and He said they are in the process of releasing a Gen 2 with some improvements which should be on the web site by the end of July. I wonder where I could try one out?

fmsniper, Maybe I'm confused, You say that you already have the 24" pictured and plan to use the lower and bolt carrier from that one, Correct? I've also had multiple uppers that I use by sharing one lower, but I go with dedicated bolt carrier groups so all I have to do is pop the pins and install the upper. You can even have dedicated optics, But do I understand you correctly that you will have a setup that will require you to switch bolts in your shared carrier in order to go back and forth with your lower and carrier?

Nice build 49, good luck with it, How do you like the .308 JP brake? I tried a .223 rifle that had one and was amazed. I think it's the most effective brake I've ever tried. If not mistaken, I think They might have even banned it from competition because it works so well.

Weaponizer, I wasn't refering to your GI pistol grip stock, I was talking about the responses I get from some people when I try to discuss the Sage EBR or JAE stocks, Or when I say that I'd like to use a Surefire comp or one of those gas block mounted aftermarket SOCOM type sights instead of the original setup as on your gun. I don't think I'm to the point yet, where my taste is sophisticated enough when it comes to the M1A's, that I have a problem using newly designed componets to build one of these. Of course, if I already had one of the early ones in good condition, I don't think I'd want to compromise it's history/originality.