dpete

I had wondered about being that close to the inside of the mag. I'll have to do some measuring again on the Pmags and ASCs that I have and do some considering. The stoppage part of it I hadn't thought of. Thanks

LOL, I already have 3 other ARs that I load for. A 5.56 Colt M4 and two 300 Blackouts, one a 16" carbine, the other an 8" pistol. The 2 blackouts may not count though because they both shoot the same bullets equally well.

What are you seeeing there that I'm missing? It was some of your past posts that got me thinking about trying various lengths.

I just got back from my latest range trip and I'm smiling. Its nice when a plan comes together. The first target group is the charge weight ladder which I shot last week. Nothing amazing jumped out at me during my round robin shooting, but the 48.7gr & 49.0gr charges had roughly the same POI centers so I went with 48.8 as my charge weight. Hodgdon lists 49.0gr as top for CFE223 in a .308 and I wanted at least a little room below that. The second set of targets is what I shot today. All of the charges were 48.8gr of CFE223 and I stepped up by .005" for each group starting at 2.790". Thanks to reading past posts here and taking the advice I received in my earlier post about cartridge length I pulled everything I had loaded below 2.790. I stepped up to 2.815" instead, which is as long as I could go and still have clearance inside the Pmags I have. The lower left target is the 5 sighting shots I took before starting the round robin with the 6 lengths. The 2.800" group is similarly shaped to the previous one I shot last week and I found it amazing how much the groups closed up as the bullets lengthened. I think 2.815" is going to be a winner with this load. Hornady 168gr HPBT Match #30501 Rem. .308 cases CCI 200 primers 48.8 gr CFE223

Compressed loads are something I want to avoid. That is why I'm concerned about getting the COAL too short and increasing the pressure too much.

Hmmm, for some reason I never thought of physically measuring down to the powder surface inside the case mouth to figure out how deep the bullet can go before starting to compress things. Thats a great idea! It will at least get me in the ballpark of knowing how deep is too deep, which with bullet seating can be bad as oppossed to some things which way deep is GOOD. <thumbsup>

I was at the range this past Thursday doing the round robin OCW ladder loads and came up with what I think is the load to go with for my rifle. I'm using CFE223 which Hodgdon lists 49gr as the top load for 168 HPBT bullets. I'm using Hornady #30501 HPBT 168gr bullets. I started with their 49gr load and went down in .3gr increments, then did the round robin ladder upward through 49.3gr. No serious pressure signs were seen, even on the 49.3gr fired cases. They were almost identical to the midrange loads. The 48.7 and 49gr loads were almost identical in target placement and pattern so I think I'll load a small batch of 48.8gr to stay under max but still stay within the good zone. Now my question. With 2.80" listed as COAL for these bullets, what kind of length range do I dare test to see if I can further reduce the pattern? I have seen where others have found sweet spots slightly above 2.80" and some below. How deep can I seat these bullets before I start running into excess pressures due to bullet depth? I will be doing the round robin ladder method once again for these 48.8gr bullets at different depths and checking for pressure signs on each case as its fired. The barrel is a Criterion 18.5" lightweight profile sold by Fulton Armory, and the upper/lower/BCG is all Aero Precision.

I can't comment on those but I do know the trigger in my Aero Precision 308 LPK is very crisp compared to the milspec triggers in any of my AR15s. To me its almost as crisp as the one I had in my Remington 700 BDL. No comparison to everyday milspec triggers.

The last two parts that I have been waiting for finally arrived from Aero Precision. Everything was here and waiting for the lower and gas block. I put everything together last night and went on the first function range trip today. First was 3 rounds in a 20 round Pmag. Bang...eject, look at the bolt and make sure its closed, find ejected casing, all is good to go for #2. Bang...eject, yesss! Third and final shot of the 3 went bang and the bolt held open...BIG YES! Then switched to a 5 round ASC mag that I intend to use for hunting. Same results, 5 bangs, 5 ejects and bolt held open after #5. All told I put over 50 rounds through her tonight without a single hiccup. Two different ASC mags and 3 different 20 round Pmags. I am a happy camper. In case you were wondering about the name, Last year I bought my first two ARs (a Colt 6920 and a upper/lower for a 300 Blackout, both rifles in FDE/black). My wife promptly named them Thelma and Louise. Then an all black 300 BLK pistol grew from parts and she christened it Babette. Since this 308 AR is obviously bigger than the other three, Bertha seemed appropriate, and best of all she runs like a top!

Thanks! I hesitated about the price too at first, until I priced out what the separate similar parts would cost. I think it came out to allowing about $100 or so for the 15" hand guard I used. The simpler barrel nut and rock solid connection between the hand guard and upper sold it for me.

She's done! See post #8 in this thread.

ITS FINALLY DONE! After waiting almost 3 weeks for Aero to get the lower and gas block back in stock they came in today and she is done. Total weight as seen here is 10lbs 2oz with an empty mag. Its bathed inside with CLP right now and I've worked the action by hand and ejected an empty shell and loaded a dummy round after it. Ejecting the empty and dummy went just fine. I had the bolt/chamber headspaced today and the gunsmith said he rarely sees chambers and bolts that well matched. As he put it a zero, not + or - anything. So far so good and now I wait for decent weather to get out and shoot it. In the meantime how much should I work the action by hand?

I just got back from the local gunsmith and the headspace is perfect. He said its rare to see a bolt/chamber combination this well matched. Now I've got the peace of mind to continue the build and not have to worry about a headspace issue.

I thought 2 o-rings was excessive too. Right now all I can do with it is things like this, and plot and plan.

I'm waiting for the lower and gas block to arrive from Aero. They were supposed to be back in stock last week.

UPDATE!! I removed the extractor (had a devil of a time pushing it in enough to release the spring pressure on the pin) and found 2 o-rings around the spring. I put the BCG back into the upper and it quite easily slide into battery. Not as easily as my 5.56 and 300 Blackouts but easy enough to do it with one finger. I had the same devil of a time getting the extractor pin back in but all is back where it belongs now. What is the best way to remove the ejector retainer pin to prevent the plunger from flying off to who knows where when the pin comes free?

The dummy round is a hornady match 308 that I pulled, dumped the powder, deprimed and reseated to 2.700 I also tried a pulled, unfired Remington 308 case without a bullet. The only attempts to get it into battery have been pushing on the BCG with the base of my hand. The ton of pressure I spoke of is more than I can exert without causing pain. I'm not going to go bashing the BCG on to a block of wood or something like that to try to get it into battery just for the sake of doing it. The main reason I asked is my other 300 Blackout and 556 ARs push into battery with a bullet loaded with finger pressure but they also have 100s of rounds through them already. The anticipation and this waiting for the lower to arrive is getting me antsy to get this 308 done and I'm probably over thinking things.

Stripping off the extractor was the route I was thinking about.

1. Yes 2. Nothing but a dummy round so far. 3. I am using a dummy round. 4. There is a ton of pressure, so much so that I haven't been able to get the dummy round to chamber at all so no ejection yet, and the charging handle is installed.

As I wait for Aero Precision to get stripped .308 lowers back in stock I did some fiddling with the rest of the parts I have. The barrel is on the upper, and the BCG and charging handle are in place. With the chamber empty I can push the BCG into battery with 1 finger. It pops right in. If I put a dummy round into the chamber and pushed the BCG forward. No way would it go into battery! Now these are brand new parts, NO lube has been applied yet and since I don't have the lower yet I can't use the buffer spring to slam it home. Is it normal for the extractor and its spring to be so tight that it won't allow a BCG to go into battery by pushing it? I haven't tried taking the extractor off of the bolt yet to see what that does. I thought I would ask here first and get some advice from those way more knowledgable than I am concerning a .308 AR.

Some more parts came in today and since I am still waiting for the lower and gas block to complete things I took some weights of the pieces I have. The Aero parts are noted. Weights so far: Barrel = 2# 8oz Criterion 18.5" lightweight profile from Fulton Armory Brake and washer = 4oz Bully Brake from Overkill Customs here in WI Upper & barrel nut = 1# 3oz 1st part of Aero enhanced upper combo 15" keymod handguard = 9 oz 2nd part of Aero enhanced upper combo BCG = 1# 6oz Aero NiB Stock, spring, buffer, & RE = 1# 3oz Pistol grip = 3oz LPK = 4oz Aero 308 LPK Total of these parts = 6# 12oz Right now I can't remember if the charge handle was in the upper when I weighed it so the total might be a tad heavier by a few ounces. Even if the lower and gas block amount to 2# total I'll be looking at around 9# total for the bare rifle. Add in about 1 1/2# for scope, mount, sling, and swivel rings it will be pushing 11# or so I think. How close am I?

From the sound of those a .308 guage set will work. Now to see if a local gunsmith can do it once the rifle is finished.

For now I'm staying with the trigger in Aero's LPK. I've read reports its better than the usual milspec triggers in ARs, which I have gotten used to. I already have a Nikon 3X9X50 scope waiting for its new home to be finished. Hopefully I can get an answer on headspacing the bolt to the barrel.

Yes I know its missing a few pieces but at least I know the rest is on the way from Aero Precision. The heart of the rifle will be an Aero 308 lower, the M5E1 upper receiver/keymod handguard, their 308 NiB BCG, and 308 LPK. I hope to see the rest of the parts come in this next week. The barrel is the 18.5", .308 AR, Light Weight, 1X10 twist, chrome lined, match quality, by Criterion sold by Fulton Armory, with a Bully Brake from Overkill Customs on the end. 20 round Pmags and 5 round ASCs for hunting. I've been reading as much as I can find in preparation for building this rifle and after reading about checking headspace I have a question about checking it on this barrel. On Fulton Armory's site they call the chamber a hybrid. "Our Hybrid Match Chamber allows use of .308 Win & 7.62x51 mm NATO Calibers" http://www.fulton-armory.com/barrelfatitan185lwcm1x10750gasblockchrome-lined.aspx I know both .308 and 7.62 headspace guages exist. Which one would give an accurate indication of proper headspace? I only intend on using commecial brass/bullet handloads in it and not wanting to risk anything I thought I'de ask those with way more knowledge than I have.

I bought a new one.