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Lane

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Everything posted by Lane

  1. Lane

    My first 7.62x39 AR

    I finally pulled the trigger on all the parts for my first 7.62x39 AR build. I'll start with a list of what is has shipped already, or soon to be. I'm not in a rush to finish this build with the cold weather, but I am excited to break in the upper. GM 21" gunsmith's barrel with no gas port. BCA side charging upper/7.62x39 BCG combo (wanted the dual charging, but they aren't in stock/on sale; compromise for the price). Standard 80% lower with pistol grip. Debating on no hand guard at all with such a thick barrel; but 15" minimum length. No idea what buffer tube length, buffer weight, or stock. I want a light weight stock because of the barrel weight for sure. Standard Mil-Spec LPK; maybe sprinkle some sand in for a good AK-47 comparison gun. C Products Magazine. Upper warming up before the new year for sure. Build photos to follow.
  2. Lane

    My first 7.62x39 AR

    Only had three rounds left after today's sighting in. I drove all over; perhaps 100 miles, to get two more boxes of factory brass. I'm curious to see groups before moving on to 150 grain reloads. I shot the .22lr with the timer afterward; and for some reason it missed another shot in the middle of the string. I don't know why that is, but I'm still surprised by the difference in input volume for those recorded shots. I believe it's simply missing on rounds that don't go supersonic for whatever quality reason. Those were the last two magazines of total trash ammo I have; so hopefully the next box will perform more accurately in terms of sound per round. Might as well test a magazine of everything I have and see what I get back in terms of data. I was looking over these last images and I think I see another dead tree about 10 yards beyond. I'm not sure if I can see it from my rest; but I plan to stretch it out a bit more the next time I go out. If I can get 10 yards there and 10 more on the other end, that's 90. Thought I would run through the hardware in my mind for the shot timer since the software is so close to finished. The micro was $8.47, though now unavailable in this form. Charger was $1.50, DC/DC converter was $1.60. Piezo pickups are $0.50 each; three in an ideal design. Mechanical rotary encoder (cheapest possible) is $0.20. The protection diode was $0.25, and the transistor, $0.07. I can't count the buzzer because I was never able to purchase any; the order was canceled because of low stock. I had to harvest these two from a LiPo alarm unit; Free (same for the batteries I had on hand). Total cost of the shot timer was $13.59. That's less than I spent on 20 rounds of Winchester 7.62x39 today... Bad weather coming; some 12+ hours of sustained 40-60 MPH winds. Not sure when I will go out to shoot again, but I'm reasonably sure this gun shoots better than me. Made me start thinking about a trigger upgrade and a lead sled...
  3. Lane

    My first 7.62x39 AR

    I bet some of the neighbors heard my range reports today; I certainly heard a number of theirs. Started out at 30 yards, made some small adjustments and then moved out to 71 yards (65 meters); that was the easiest thing to drop today. Had to make some more dramatic scope adjustments and almost ran out of ammo; but the last three are pretty tightly grouped. Two through the same hole lower left of the center ring. Don't mind the tear on the target; that's from trying the 30 yard log which almost always explodes on impact. I kept shooting at the other target and apparently grazed it.
  4. Lane

    My first 7.62x39 AR

    A few updates I keep forgetting to report. The lithium battery situation was resolved by accident. I was annoyed that it died again for "no reason", when it dawned on me; the computer USB port isn't hot enough. Plugged it in to a specific type of high current USB power adapter and it charged up in about an hour. The WiFi password is now obscurificated on screen (but can still be edited); and I added "push/twist to adjust", in addition to the existing "click then twist to set individual digits" for the numerical values. Most of them don't adjust very far, so it's better to have both options. The "<" on the display next to a number indicates one that can adjust with a push/twist of the "purple" knob. Weighed this with optics, and the Ceratac .308 on the bathroom scale. The 7.62x39 comes in at 9.0 pounds, where the Ceratac is 10.4. I took it outside today to sight out a good 100 yard target, but I don't see many clear spots. May need to clear some brush to get something usable. This gun definitely tired out my left arm in a few minutes of screwing around; but it was always designed to be shot from a rest... I can get a few good shots off before I get tired when shooting from the shoulder though.
  5. Lane

    My first 7.62x39 AR

    Spent another long night on the timer and got the settings selection/edits working. That required a fixed width font and there weren't many choices loaded in the font generator utility. I think it's kind of ugly, but fonts don't take up much space. If I find any better monospaced fonts, I will load other options. One thing I need to work out is password obscurification. For some reason it's not counting the .length() properly, which appears to be a bug. I also need to terminate entry so you could for instance change the WiFi SSID to something shorter without having to clear extra characters one by one. A few more things to tie back and forth to reduce unnecessary file reads/writes; but some of that was finished up last night too. Course loading happens in the menu and it pulled into the shot timer from a global for speed; even with a few 2k byte variables, I still have more than 50% of free RAM for operating. Copper showed up, but I haven't had a chance to clean and lube the lathe yet.
  6. Lane

    My first 7.62x39 AR

    So; I found some temporary scope rings after all, and this is what it looks like assembled. I still haven't taken it outside for a good once over, much less sighting in. I have some issues seeing/focusing on the reticle; but that might just be the uselessly short distances I was looking at. It was dark by the time I got it mounted on the rifle.
  7. Lane

    My first 7.62x39 AR

    Drove by the local rod and gun club today, and it looked pretty small. After I got back home I looked it up on google earth; sure enough their longest range is 100 yards. I can do that here in the winter without much trouble. So I dropped another ruler on the map, and just need to find some kind of backing material to place a new target. I really can't get much further than 100 yards though because of the density of trees. Shopped around for those elusive Armalite style 80% lowers for the .260 rem build and found at least two; maybe even three or four. I am not positive the Genesis CNC would work but I'm sure a quick email or phone call would work that out. The photo of the first option looks exactly like the Ceratac lower I have here already. I'm beginning to believe that is an option still, but I won't know for certain until I have an upper in hand. SMF Tactical offers both Armalite A and B style 80% lowers for a premium price. $99-$120 (black hard coat) http://www.lowerreceivers.com/contents/en-us/p121_308lowerreceiver.html $215 https://www.smftactical.com/308-80-lower-receiver/ Sale $104 https://genesiscnc.com/product/gen-2-80-lower-receiver-308-lower-flash-sale/
  8. Lane

    My first 7.62x39 AR

    Not much of an update here; been busy with other things. Picked up a scope today, but of course the rings I have on hand aren't quite tall enough. There is some software that works with it; but I would rather work something up on a spreadsheet at this point. I wish to understand the math completely... I think I could use some other rings the short term; but I already ordered new ones that will work. Not sure how much of a rush I will be in to sight it in; though there are a few days coming up that will be above freezing at least. I read that I can shoot at the local rod and gun club without a membership. I may take a trip over there soon and see what is available. Sure would be nice to get out to 200 yards once in a while for testing. Since I had to place an order anyway; I added a quick trim die for the 7.62x39 since they all seem to come out long after first fire. Looked for the more expensive brass ammo today; but that one place was out of stock. Could have asked at the gun store to get something ordered; but they were of very busy as usual. Haven't gotten much further on the shot timer, but I did have a thought about how to resolve this last issue. It's not elegant or efficient, but it will certainly work. I should be able to implement the selection markers in about an hour; and then finish up the code to drive them after that. I've searched a few more times for this particular microcontroller module (used in the shot timer), and it is certainly last year's product. It has been superseded in every online marketplace I can fine. Those searches did turn up the designer of that original product though; I can't imagine they shred and recover old designs like that. I'll try to send out a few e-mails and see if I can find some old stock somewhere in China. I would be happy to get 10 or 20 to keep around for various reasons. I have everything here to make up a few 150 grain loads to test after sighting in. Whenever I feel the need to take a break from code, I'll make some. I don't spend too much time in the Reloading thread; but what do you all use to clean cases? I'm not personally ok with vibratory or tumbling. I wash; but still don't know where to dump my waste, or how to store it. Lead is my only concern; and while I do lead the land with projectiles, I figure shitt flows down hill. This gun might be a good choice for 108 grain solid copper projectiles though. Turning some of those is on my to-do list from this thread. Update: Just ordered three diameters of solid copper rod (.250, .375, .625); I'm sure you can figure out which calibers those are each for. I almost ordered a stainless rod too; but it was pretty expensive. I'll do that later after I recover all the C101 shavings. The Unimat is waiting...
  9. Lane

    Lets See your 300 blackout pistols

    What do you like to shoot out of it? Or is it still a virgin?
  10. Lane

    My first 7.62x39 AR

    I doubt it. I think I have a good idea already. And so far as I can tell that only happens in the southwest... I'll let you know for sure after fall shoot. I'm kind of pissed about the hardware situation, but that's what I get for crossing chinese new year. Every single one of them had time to rock out new designs when everything else shuts down for weeks. Here I am having to redesign the timer for all that new hardware... Might as well make it a ns timer in the new design; FTW. Saw a 1.6GHz SoM for about $70 the other day. Pretty sure that could actually see ns resolution with a bit of work.
  11. Lane

    My first 7.62x39 AR

    I looked at Accurate 1680; but didn't have load data for that across the board. I've also been eyeballing IMR 4198 as a good choice for both cartridges through much of the projectile weight spectrum. I did compare the powder weights and projected speeds between the load data I found for 311/312 with CFE BLK in 7.62x39; and don't see any reason to be concerned (they were exactly the same). The shop I went to today had a chrono on the shelf; which I might use to start with, then cut in half to build on a 10' span later. That's a project for the future though, as I still need to get sighted in with a scope. I tried to buy more of these shot timer boards with the larger screen; and can't find them anywhere for less than about $20. Seems like I found someone that had mis-priced the unit. Should have ordered 10 to begin with. The new ones I've found all have relocated the buttons such that my current design doesn't work at all. There is a different module available for about $15 that has three buttons below the screen, and is mounted 90º clockwise on the board. These may be the only two "blueberry" control prototypes ever if I can't find more of this particular part. Pretty close to being able to mail out a fully functional unit one way or another...
  12. I've never driven through the desert myself. Is this single sharp rocks that ruin the tire, or a combination of large sharp rocks that shred it? I live on a rocky mountain, and did manage to rip a valve stem off a tractor tire (full of ballast no less); trying to get close to rocks. I don't mess around with that anymore, an expensive lesson for sure.
  13. Lane

    My first 7.62x39 AR

    Found a pound of CFE BLK locally for less than I would pay to order one online with the more standard $10 hazmat fee. I picked that up; and some other odds and ends. While that shop has loads of projectiles; I didn't see a single box of .310, .311, or 312. I'll be fine for a little while longer in that regard; but it would be nice to test at least one other diameter side by side. I spent quite a few hours on about ten lines of shot timer code last night. That's how you know you're almost done by the way. One of my fixes broke something else which turned out to be a hack from a week or two ago. Everything is back to stable running condition; and only one more real project left on this 1.0 version of the code. I poured over it for a while last night but didn't fine a solution quite yet. It looks like there is a whole separate UI library built in; but I didn't implement it early on. My only problem here is selecting or highlighting characters in the settings menu; this would inform the user what is selected, allowing changes from the display instead of the web interface. I am unable to invert the display of individual characters, and adding a manual highlight is a huge pain without a fixed width font. I'll see if I can get that worked out tonight one way or another. I tried to get a range report yesterday but it just wasn't happening. Looks like I'll be saving the last box of factory ammo I have on hand for sighting in the scope; then on to reloading after that. Been trying to decide on a lower for the upcoming .260 build. There are precious few options that don't have a DPMS style radius. I am not sure if Ceratac will sell me a bare 80% lower; and I'm not positive it would work (though I think it would with a different FCG position). The other "true" Armalite style 80% lowers are all more than twice as expensive, and I only recall finding two options for that when I was researching that original Ceratac .308 build. I assume I'll want that Armalite upper in my hand for comparison very early in that build process.
  14. Lane

    My first 7.62x39 AR

    Picked out an additional scope for this build. It sort of came to me out of thin air; an epiphany of sorts. It even helps me name the gun, so I'll incorporate that into the shot timer as another easter egg... I haven't talked much about accuracy because I didn't care about it early on in the build. The second shot I ever tried to fire on target blew the whole cardboard off the frozen log. I was pretty sure it was a tack driver from day one. The two shots I took today with the pop up sights were dead on where I aimed. I will of course work up a range report soon, but it may well be the best one I own in terms of shoulder firing accuracy. I priced out a mostly Armalite brand .260 Remington build. Wilson Combat barrel, and an 80% lower. That will be my next experiment when I get bored. I presume it will take me some weeks to buy all those parts. I won't be bored until after spring shoot for sure...
  15. Lane

    My first 7.62x39 AR

    So the 150 grain projectiles look like they are just what I wanted for this. While researching powders that will work for both 300 blackout and 7.62x39, I found this on the Hodgdon site. The reloading data specifies .310" for light projectiles, .311" for medium weight, and .312" for heavies. I don't claim to understand why at the moment; but it does explain why I couldn't find any 150s in .310". CFE BLK is the only powder I can find load data for across the wide array of 300 blackout and 7.62x39 projectiles. Unfortunately it's out of stock at the usual suspects. I found it in stock at some other places; but one of them wanted $28 for hazmat and another $12 for the ground shipping. I might have to see if a local shop has it; or wait for a better deal.
  16. Lane

    My first 7.62x39 AR

    This makes me laugh. That is precisely what I did to my extractor last night with 1000 grit. Today's brass looks almost flawless. Don't mind the unfired round; I'm taking measurements since the 150 grain projectiles showed up today. Unfortunately almost every once fired case I have is over length which is something I've not seen with .223 or .308 when reloading.
  17. I'll tip my hat to that as well. 98 saved me a lot of trouble on my first .308 AR; and hasn't stopped offering valuable comments or advice since. This is not just any old internet forum, real good people around here...
  18. Lane

    My first 7.62x39 AR

    This is a quick peek at the shipping menu code. Also a look at the faulty and incorrect DC/DC converter. Finally a tiny window of the code I'm working on; and memory usage. Bare metal is going to be so much more fun (and accurate). Live free or die.
  19. Lane

    My first 7.62x39 AR

    Here is my brass from extractor testing. I stripped the bolt carrier again and tested a new o-ring. It has the same issue, and cannot be assembled by hand with it inside. The o-ring that came with the bolt originally has crush marks on it. I think reducing the volume of the o-ring by about 25% would allow it to assemble and function as intended. I'll photograph how it actually goes together with a standard o-ring when I try a reduced o-ring. I didn't fell like cleaning up to take pictures of that yesterday. I did polish out the extractor edges quite a bit so the next rounds shouldn't have anything more than magazine and bolt marks; these already look pretty good in that regard. About to dive in to the shot timer code and I made a final to-do list last night. Still need to dig out some more AA battery holders for the new hardware build, and make something happen. My goal is to get two or three sensors in that design. New parts are still a few days out; but those don't really have much bearing on this build. I put some temporary BUIS on the 7.62x39 because of the broken dot sight. The rear takedown pin feels a lot better, but I'll pull it out later to measure and fill the dummy detent with JB weld when I get some new ones. I need to make one more special pin for another polymer lower that is on the way. Turns out the scales I ordered a while back aren't going to show up. eBay seller has about a 36% satisfaction rating all the sudden. I'm sure I'll get my money back; but I won't have scales to modify coming this week either. Don't really care about that data short term, as I still need to build a stupid long optical chrono to do any actual testing.
  20. Lane

    Hello from New Hampshire

    This I get. This is why I think it's a great idea... I live in a state where duct taping a knife to my gun makes it an illegal assault weapon. As if bringing a mounted knife to a distance gun fight is really going to be a problem. Go figure. I assume you want one that flips out based on your initial inquiry? That Geissele mount does look bulky, but shouldn't be all that heavy. Since I can't have a bayonet here; I haven't researched this at all. I don't know that you'll find a lot of people that want to weld a hand rail. You could modify some rail attachment parts and bolt them on for mounting something unusual on the rail as opposed to using the gas block. Your milage may vary; but I am certainly curious to see what you end up with.
  21. Lane

    My first 7.62x39 AR

    Fired off two rounds to inspect brass, and the extractor was still gouging a bit. I stripped the bolt carrier group which was immaculately clean to find out that the extractor hadn't worn in at all. I couldn't move it with any amount of pressure, and it still looked wrong. I wasn't even able to clip a cartridge in to the bolt with my hand. I'm honestly not sure why it was working as well as it was given the situation. I searched around for other people having problems with this; and sure enough two reviews of the bolt only part mentioned exactly the same problem I was having. Apparently the o-ring inside occupies too much volume and keeps the extractor from moving appreciably (at all in my case). Simply removing the o-ring was enough to resolve that problem, and now the extractor pin can be removed/replaced with finger pressure. Two more test rounds showed nicer brass; but there is still burs on both ends of the extractor. I'll strip it again and polish those... One of the reviews mentioned grinding it like a shark tooth, I think I'll be fine with 1000 grit sandpaper. I'll try the other o-rings I have laying around and see if any of them fit better while I'm at it. I think you're saying I'll be ok here with those Speer .311" projectiles. I shoot regular off the shelf 7.62x39, but I plan to keep this gun as a brass queen. No cheap steel case ammo in this particular build. The Lee loading data says .311" projectiles. The specs I can find on 7.62x39 says 7.92mm projectile, which is .3118"; some call this .312". I'm just not sure why so many vendors sell .310" for the 7.62x39... I measured the projectile in the Winchester rounds I have, and they appear to be .311". I gather that shooting .308" projectiles would be a little like a hotdog in a hallway; launching bullets with less pressure and decreased accuracy.
  22. Lane

    Hello from New Hampshire

    Sounds like you got this covered sir. I toyed with those numbers a while back, and decided on a long barrel by accident. I don't regret it for a minute; and that last build balances perfectly in my left hand, (right handed shooter). You can mount rail attachments if needed; or just bolt on the component you need. I don't shy away from drilling or cutting a rail to make something work; that what makes it unique.
  23. Lane

    My first 7.62x39 AR

    Runs great; and the brass looks wonderful. I just want to make sure everything is working perfectly. I saw someones out of battery picture the other day and I'm not interested in that kind of testing/experience... My split times were 0.5 seconds longer than with my .308 build; even when charging manually. The .308 moves so much more on the shoulder that I have to take time to fire again. The 7.62x39 only takes that much time to charge a new round. There were some audio file images posted a while back that show them side by side. You can see a slight tick between shots when I charged the next one on this straight pull build.
  24. Lane

    Hello from New Hampshire

    Why not a full (or near full) barrel length handrail; and a bayonet on the bottom of the rail? Not sure if you wanted a bi-pod too. Welcome indeed. What's your reasoning on the 20" barrel? I have a long barrel on my 7.62x39 build.
  25. Lane

    Little guy needs a few years

    I laughed out loud at this too. One guy that hunts on the adjacent property sent me pictures of a bear that was in my back yard during hunting season (live update because he has a cellular connection). I didn't go looking for the bear; but he said it ripped his camera off the tree and pounded it. I would totally piss on the bear if I actually climbed a tree.
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