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ejection/extraction trouble shooting: adjustable gas blocks and powder burn rates
- Thread starter georgehwbush
- Start date
jetinteriorguy
New member
One of my rifles quit locking back when empty once, I pulled apart the bolt catch and somehow the spring got messed up. It’s been quite a while and I don’t remember how the spring got messed up but I put in a new one and it’s been 100% ever since.
georgehwbush
New member
amp 44: different mags? errr no.
When a magazine feeds ammo, but fails to lock open on the last shot, it is unlikely that short stroking is the reason.
What is more likely is that the magazine spring is just slightly underpowered.
OR, possibly the follower is dragging just enough to not lift into position to activate the bolt catch, in time.
The "in time" part is what matters.
Check for wear or damage where the follower and bolt catch engage. There probably isn't any, but check.
The empty magazine operates the bolt hold open properly when you open the action by hand, right?
It feeds ammo properly, right??
Since the mag feeds, that proves the bolt is coming back far enough to pick up the next round. Is it possible the bolt is coming back enough to pick up the next round, but not far enough to allow the bolt catch to activate after the last round? Yes, it is possible, but I think it is more likely to be an issue with the magazine, or the bolt catch. Testing with a different magazine will rule out some factors.
Good Luck.
What is more likely is that the magazine spring is just slightly underpowered.
OR, possibly the follower is dragging just enough to not lift into position to activate the bolt catch, in time.
The "in time" part is what matters.
Check for wear or damage where the follower and bolt catch engage. There probably isn't any, but check.
The empty magazine operates the bolt hold open properly when you open the action by hand, right?
It feeds ammo properly, right??
Since the mag feeds, that proves the bolt is coming back far enough to pick up the next round. Is it possible the bolt is coming back enough to pick up the next round, but not far enough to allow the bolt catch to activate after the last round? Yes, it is possible, but I think it is more likely to be an issue with the magazine, or the bolt catch. Testing with a different magazine will rule out some factors.
Good Luck.
some more testing done: with 43.1 grs of reloader 19 and the 107 gr, sierra match king, they are clocking 2922 ft/s 15 ft from the muzzel and grouping at 0.785 in. cycling well but not always locking back on empty mag. so that's where we stand right now.
Good shooting.
The cycling has improved with this slower powder, has it not? I think you are in the right direction. Gas block fully open now? I would give it another half turn if not.
Not my first choice to correct cycling issues, but it has worked for me. I would cut coils off the recoil spring, half coil at a time. It enables the BCG travel back a bit further with same energy.
I also went shooting my ar-10 in .243 win yesterday. 10-shot group of 0.8" at 100yd. I have 38.2gr Ramshot hunter behind 100gr speer spbt bullet. MV is around 2850fps. Good enough for me. Will take it to 200/300yd next week.
I'm new to this caliber. A bit disappointed when I started with cheap 75gr flat base varmint bullet. Ballistically it was slightly better than 5.56 NATO. The 100gr spbt makes huge difference. It is a keeper.
-TL
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georgehwbush
New member
tangolima; "gas block fully open now?"
in fact no. with it full open, it doesn't eject properly and leaves swipe marks on the case heads, it is a bleed off type adjustment, and i'm bleeding some of the presure to get it to cycle correctly. the gas-block instructions says open four complete turns for full open and open more to bleed off. they do not reccomend closing to reduce pressure but opening more... up to 16 turns total. i am at six and an half right now, it is cycling perfectly. but just doesn't "always" lock back.
amp44: i will try another mag and see what happens. also have a buffer weight set ordered, just in case.
in fact no. with it full open, it doesn't eject properly and leaves swipe marks on the case heads, it is a bleed off type adjustment, and i'm bleeding some of the presure to get it to cycle correctly. the gas-block instructions says open four complete turns for full open and open more to bleed off. they do not reccomend closing to reduce pressure but opening more... up to 16 turns total. i am at six and an half right now, it is cycling perfectly. but just doesn't "always" lock back.
amp44: i will try another mag and see what happens. also have a buffer weight set ordered, just in case.
georgehwbush
New member
tangolima: i have no doubt now that with a little testing, you can get half MoA out of these, the 243win is an accurate round, and the ai version is even better, it has been my experance that, (at least with bolt guns) most 243win's like the 2950 to 3050 ft/s range, that seems to find a node on 22 - 24 inch tubes. also the heaver '90gr +' pills work best, assuming you have enough twist of course.
But, i have never gotten good accuracy out of cheeper factory loads,
if all you want is proper cycling in an ar platform they seem to do that very well. but the 1.7~2.2 MoA is only good for..... nothing really.
thanks guys "and gals" for all the feed-back it helps to hear what others think about what one is doing, (one doesn't have to agree) but it helps to hear it... enjoy your freedom and your health while you have it.
But, i have never gotten good accuracy out of cheeper factory loads,
if all you want is proper cycling in an ar platform they seem to do that very well. but the 1.7~2.2 MoA is only good for..... nothing really.
thanks guys "and gals" for all the feed-back it helps to hear what others think about what one is doing, (one doesn't have to agree) but it helps to hear it... enjoy your freedom and your health while you have it.
I meant to put a bit more gas to cycle the action, however your gas block works.
I am currently loading with 100gr spbt bullet. It is long but not terribly long. It seems stabilized ok. 2850 - 2900fps is the end of the push as the primer starts having shallow cratering. I will try 85gr bullet next, where I can go a bit faster. Flat base varmint bullets are cheap. But they have much more drag. Speed drops to subsonic pretty soon and they are sensitive to cross wind. I probably can do better with better bullets. But I'm on budget. 0.8moa is mighty good enough for me. I think I can consistently hit a letter paper sized target out 750yd with it.
I found it quite easy to convert .308 brass into .243. It is a plus for me.
-TL
Sent from my SM-N960U using Tapatalk
I am currently loading with 100gr spbt bullet. It is long but not terribly long. It seems stabilized ok. 2850 - 2900fps is the end of the push as the primer starts having shallow cratering. I will try 85gr bullet next, where I can go a bit faster. Flat base varmint bullets are cheap. But they have much more drag. Speed drops to subsonic pretty soon and they are sensitive to cross wind. I probably can do better with better bullets. But I'm on budget. 0.8moa is mighty good enough for me. I think I can consistently hit a letter paper sized target out 750yd with it.
I found it quite easy to convert .308 brass into .243. It is a plus for me.
-TL
Sent from my SM-N960U using Tapatalk
georgehwbush
New member
indeed quite easy to resize 308 > 243. just lube and shove it in the full length die... but, i prefer to keep the head stamp correct. unless you are using something like mil/spec/surplus where the headstamp is caliberless .
tangolima, i know that it may sound obtuse but, i always prefer the heaver higher B.C. pills, what they lack in initial speed they more than make up for in long range performance. but that's just me.
i'm surprised that you are seeing preasure signs at 2900 ft/s with 100gr pills. it might be the powder. ? i find slower powders generally yield higher speeds with lower presures and usually only start seeing signs at around 3025 with 100gr 3000 with 103gr,
i'm sure you know what you are doing and i need to just leave it alone, just thinking out loud !
cheers
tangolima, i know that it may sound obtuse but, i always prefer the heaver higher B.C. pills, what they lack in initial speed they more than make up for in long range performance. but that's just me.
i'm surprised that you are seeing preasure signs at 2900 ft/s with 100gr pills. it might be the powder. ? i find slower powders generally yield higher speeds with lower presures and usually only start seeing signs at around 3025 with 100gr 3000 with 103gr,
i'm sure you know what you are doing and i need to just leave it alone, just thinking out loud !
cheers
The load is mid point between min and max. I could have pushed it closer to 3000fps, but I had a couple of pierced primers. I feel more comfortable with where I'm at.
Other than cost, I use varmint bullets with lower BC quite often for "emulated long range training". A lousy bullet at closer distance emulates a better bullet at farther distance, so that I can practice wind reading without going to a real long-range range.
-TL
Sent from my SM-N960U using Tapatalk
Other than cost, I use varmint bullets with lower BC quite often for "emulated long range training". A lousy bullet at closer distance emulates a better bullet at farther distance, so that I can practice wind reading without going to a real long-range range.
-TL
Sent from my SM-N960U using Tapatalk
The load is mid point between min and max. I could have pushed it closer to 3000fps, but I had a couple of pierced primers.
We may have a difference of opinion on this, but I'd say if you are getting "a couple of pierced primers" (and there is nothing mechanically wrong with your rifle) then your load isn't midpoint between min and max, its AT MAX, for your specific combination of gun and components.
Pierced primers happened when I tried to go further, 1% or 2% below max. No pierced primers where I am. Just barely noticeable cratering.We may have a difference of opinion on this, but I'd say if you are getting "a couple of pierced primers" (and there is nothing mechanically wrong with your rifle) then your load isn't midpoint between min and max, its AT MAX, for your specific combination of gun and components.
BTW, load data is from hodgedon website. I do know it is a bit on the aggressive side.
-TL
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Last edited:
Everytime I turn it on. The powder pan weighs 34.34gr. When I lift the pan off the scale, it should display -34.34+/-0.02gr. I will recalibrate if not.I wonder how many people have and regularly use calibration weights for their powder scales.
-TL
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Every time I move the scale, which pretty much means at the start of any powder loading session.I wonder how many people have and regularly use calibration weights for their powder scales.
BTW, load data is from hodgedon website. I do know it is a bit on the aggressive side.
Aggressive or timid, is just a point of view. What matters is the understanding that ALL reloading data, no matter by whom, or where published was NOT worked up in your gun, with your components.
Pressure signs are extremely good and reliable indicators, not of what the pressure amount is (in psi or whatever units used) but of what the pressure is DOING in your gun, with your components.
"Max" loads in the book are the max that they got, using their gun and components, and while one expects similar results, things with your gun and ammo can be different, either on the high side, or the low side.
I've seen (and had) some guns that show pressure signs below listed book max and some that have gone well beyond book max with no indication of high pressure at all.
IF you get pressure signs, no matter where your load is on the published table, STOP, you've gone as far as your gun wants to go. Increasing your load beyond that point because "the book said X was max" is foolishness, and may result in issues you don't want.
I did stop. Thank you.Aggressive or timid, is just a point of view. What matters is the understanding that ALL reloading data, no matter by whom, or where published was NOT worked up in your gun, with your components.
Pressure signs are extremely good and reliable indicators, not of what the pressure amount is (in psi or whatever units used) but of what the pressure is DOING in your gun, with your components.
"Max" loads in the book are the max that they got, using their gun and components, and while one expects similar results, things with your gun and ammo can be different, either on the high side, or the low side.
I've seen (and had) some guns that show pressure signs below listed book max and some that have gone well beyond book max with no indication of high pressure at all.
IF you get pressure signs, no matter where your load is on the published table, STOP, you've gone as far as your gun wants to go. Increasing your load beyond that point because "the book said X was max" is foolishness, and may result in issues you don't want.
-TL
Sent from my SM-N960U using Tapatalk