At this time of post I haven't read the 3rd page yet! From this forum and a couple of others I've seen the mention of SBD's. Now I've seen dies listed as AR type and now understand why................well not really why, just now know what SBD's are and for. Seeing many references to AR's (being semi) and not any like BAR's in mention and BAR's (or other semiauto non-AR's) might not need them? I go into this as I've reloaded countless numbers of rounds without using (or knowing I might have a die being used for this) FL dies in my setup? I FL every time I reload whether it be for every firearm (not including SG's as I don't reload them). BUT I have the die make contact with the shellholder by just a touch. Maybe this is why I don't have any issues when reloading for any of my cartridges in the AR platforms (5.56nato, 243win, 6.5gren, 6.5creed, 260rem, 6.8spc2, 300bo and 308win). I've also never measured fired cases and compared them to FL resized 1's. Maybe I will just to check on the possibilities of. I don't have any BA's with chambers of any that I have in AR's. Will I wear out my cases by FL sizing every time I reaload.................................well after more than 20 times using win super-x 264wm cases I have yet to have any issues using the same 100 cases over 38 years. On my sierra 140Spbt's I load with imr4831 over what their (sierra 5th I believe) states by .5 grain.
Semi auto advice needed
- Thread starter CNY Yote Hunter
- Start date
Help Support Long Range Hunting Forum
With much experience, it can be done safely once you learn how to measure various points and exactly what you can get away with.
My son has an AR10 (?) in .308 WInchester that gives him "and me" a PITA every time he takes it out at the range. He built this one from the ground up also. There are so many variables that go into these builds that makes it almost impossible to diagnose any issues one may be having with one. One has to be a master in ARs to figure them out!! The gas blocks, adjustable or not, mid-barrel or not, bigger springs, factory or not, heavy or light, bolt assemblies and on and on!! Then we have the issues of magazines, and again on
and on. If the next remedy doesn't work it is now going back to the factory!!! The gun will run fine, then for no reason stop ejecting the spent cases;yet, it shoots cloverleafs!! I wouldn't worry about your ammunition not working in his AR. I know this doesn't answer your question, this has just been my experience with an AR!!! I reload for him and myself, but refuse to waste time prepping and developing a load for his rifle until he gets it to run properly. As for your friend's rifle, your ammunition could have too much pressure and that's causing the problem??
Last edited:
In a bolt action rifle it is very easy to get your headspace and resize your brass accordingly. Just bump it back till it barely closes with a touch of resistance. Turn the die in maybe 1/8 of a turn, and you should be good. I sometimes use a Lee Collet and a body die for 308. Now I just use an RCBS X Die. I have on military brass had to remove material from the shell holder to get the appropriate headspace.
I measure constantly. There are probably six sets of calipers on my bench for various reasons. Length of case, OAL, COAL, Base to shoulder with appropriate comparator insert, base to ogive with insert, neck tension, neck wall thickness, web expansion, etc. The 1st thing I do when I shoot a new rifle is take whatever brass I just shot, examine it, and measure each one to the shoulder, take the average, and write it down in my journal along with that rifles information.
If you are not measuring base to shoulder with a comparator on a semi auto, there is a very good chance that you are working your brass too much or will wind up with a round stuck in the chamber. Particularly if carbon builds in the chamber. I saw that just last week with a guy running wolf bullets and a suppressor. Something as simple as not enough lube on the neck when the expander ball pulls back up and through can stretch a case out of spec and cause it not to chamber. Been there, done that, got the t-shirt. Then again, over the last 35 years of loading for shotgun, rifle, pistol, and spitball. I've accumulated my share of t-shirts
I measure constantly. There are probably six sets of calipers on my bench for various reasons. Length of case, OAL, COAL, Base to shoulder with appropriate comparator insert, base to ogive with insert, neck tension, neck wall thickness, web expansion, etc. The 1st thing I do when I shoot a new rifle is take whatever brass I just shot, examine it, and measure each one to the shoulder, take the average, and write it down in my journal along with that rifles information.
If you are not measuring base to shoulder with a comparator on a semi auto, there is a very good chance that you are working your brass too much or will wind up with a round stuck in the chamber. Particularly if carbon builds in the chamber. I saw that just last week with a guy running wolf bullets and a suppressor. Something as simple as not enough lube on the neck when the expander ball pulls back up and through can stretch a case out of spec and cause it not to chamber. Been there, done that, got the t-shirt. Then again, over the last 35 years of loading for shotgun, rifle, pistol, and spitball. I've accumulated my share of t-shirts
details on build, por favor
The only information that I have is that the entire build is Aero Precision, upper, lower, gas block, buffer spring. He had some issue with the spray finish from the outside of the bolt getting inside of the bolt where the locking lugs slide back and forth. That he polished out by hand and the lugs seem to slide better. He also changed out the heavier buffer spring to a regular buffer spring and that seems to have helped, but the bolt does not lock back on the last round, and he's looking at another magazine. I'm a blued steel and walnut stock kinda guy so I don't know much about this stuff. I only know that he's got a couple of these AR builds and they seem to have bugs in all of them.
If his bolt isn't locking back that sounds like undergassed. But there were certain AR 10 mags that weren't necessarily reliable at locking the bolt back. The 4 shot metal mag that came with my DPMS was that way and so were a couple of my Magpuls. If it isn't ejecting due to the bolt not coming back far enough, I would ask aero what their port diameter should be And measure. If that's in spec look at the gas key and then bolt rings and fit. As he may be binding or losing gas there. If he has an adjustable block how does the gun react when the block is opened or closed. Work systematically through each system. There are a lot of variables but they can normally be worked through by process of elimination.
I've built quite a few Frankenstein builds. Remarkably my most thrown together build done with spare parts, almost nothing came from the same place, runs as well or better than anything else I have. Except for the AK, and we feed it steel cased garbage.
Keep us posted, it's a learning opportunity. Im glad to help as I'm sure some of the others here are.
I do buy a lot of their products, but have yet to have a 308 barrel from them (only cause it's usually out of stock). Which barrel from them are you talking about? You mentioned spray finish, so how was that done? Was it completely together or disassembled or partially disassembled? PM me if you feel it would be better?
MSURunner
Well-Known Member
Cycling issues with an adjustable gas block are generally REALLY easy to fix. Here is my process that usually gets the gas system tuned within 5 shots. If you have a suppressor, it can take more to fine tune it as you may need to increase buffer mass to hit a sweet spot between gas block settings.
1. Close the gas block off completely.
2. Load a single round into a magazine.
3. Fire single round.
4. Diagnose: If the bolt does not lock back, open gas block another click and repeat. If bolt does lock back, take a look at ejection pattern. 12 o'clock to 2 o'clock, potentially over-gassed/under-weighted. If closing the gas block another click doesn't lock the bolt back, look to increase buffer weight/spring. If 4 o'clock to 6 o'clock, potentially under-gassed/over-weighted. If opening the gas block another click doesn't provide better ejection (ideal is 3 o'clock), then look to decrease buffer mass/spring.
5. Repeat steps 2-4 as necessary. For reliability sake, I would prefer a slightly over-gassed AR to and under-gassed one. I'll take a bit more wear and tear on brass and buffers/springs to ensure that I will have another round in the chamber and ready to fire when I need it.
1. Close the gas block off completely.
2. Load a single round into a magazine.
3. Fire single round.
4. Diagnose: If the bolt does not lock back, open gas block another click and repeat. If bolt does lock back, take a look at ejection pattern. 12 o'clock to 2 o'clock, potentially over-gassed/under-weighted. If closing the gas block another click doesn't lock the bolt back, look to increase buffer weight/spring. If 4 o'clock to 6 o'clock, potentially under-gassed/over-weighted. If opening the gas block another click doesn't provide better ejection (ideal is 3 o'clock), then look to decrease buffer mass/spring.
5. Repeat steps 2-4 as necessary. For reliability sake, I would prefer a slightly over-gassed AR to and under-gassed one. I'll take a bit more wear and tear on brass and buffers/springs to ensure that I will have another round in the chamber and ready to fire when I need it.
"Repeat steps 2-4 as necessary. For reliability sake, I would prefer a slightly over-gassed AR to and under-gassed one. I'll take a bit more wear and tear on brass and buffers/springs to ensure that I will have another round in the chamber and ready to fire when I need it."
Precisely. Even with the adjustable gas I will generally go a click farther. Particularly in wintertime really cold weather. In summer, I may check again and dial back one particularly if temps are over 90. Which typically is Every Day with 95-105 and 60 plus percent humidity here.
Precisely. Even with the adjustable gas I will generally go a click farther. Particularly in wintertime really cold weather. In summer, I may check again and dial back one particularly if temps are over 90. Which typically is Every Day with 95-105 and 60 plus percent humidity here.
Unionsparky46
Well-Known Member
Just curious if the rounds fired out of the semi are new - never fired. If not then are you full sizing them? I was a fanatic about neck sizing my brass for my bolt guns until I found some other tricks. My first stop would be if the brass is new to headspace it. Anyone can assemble an AR platform and for the most part be good. Sometimes you get a flyer from the factory but it's absolutely a good idea to check. If its good then you don't have to worry about missing fingers!!
So if it's good on the headspace, buy a headspace gauge and a shoulder bump gauge. I used to be a fan of the 1/8 turn until my brother couldn't close his bolt with a round I loaded for him. Those two gauges will allow you to get every cartridge at least back to saami spec. Once you have a cartridge to use as a comparison, you'll be able to set your Full Length die up.
For this you'll want to get a good bushing die set. I use Redding comps as they're easily available. Other manufacturers like whidden make awesome stuff too and you can call/email them with questions. Once you get all that set up, I would bump the shoulders back at least by 1 thou then take it no further than 2 thou. Some rifle actually want more but that's where a lot of caution comes into play.
My brothers 300 win brand new from the factory hated all of my full length hand loads (once fired brass only) from my 1995 REM 700. This is how I found out how to properly measure headspace, case length, shoulder length, COAL and olgive. This is especially important after annealing. With a primer falling out seems like actually you might have a brass issue. If there's enough pressure to pop a primer out of its seat, usually the gun will pop with it,….. a lot of pressure to pop a primer out against a metal surface.
Only a few things hamper the extraction of a round in an AR platform. If the round chambers and extracts before you've fired it then we're off to a good start. Buffer tube springs have alot to do with this as well, kind of weird I know. Too heavy or light of spring rate will not allow extraction. Charging handles not transferring the gas to the right proportion, improper sized gas tube or worn out extractors will all cause this too.
In summation, all of that brass checking will at least make you confident in your brass. Basically, takes the liability off your plate and gives you a little reprieve. If it all checks out then it's time to play with the rifle. Head spacing is extremely important and a go/no go is a great start. Hope my mini novel helps!
pdog shooter
Well-Known Member
Maybe I missed it but has anybody mentioned a small base die? Paint one of those unfired rounds with a sharpie. Cycle it a few times, If the side body of the brass is scuffed, especially down near the webbing then a small base will fix. I think
