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Posted: 2/15/2006 9:40:50 PM EDT
Ok, so I just grabbed my HD AR to go outside and went to chamber a round just in case the crazy zombies are waiting for me. I have a USGI 30rnd mag loaded w/ 28 rnds of Black Hills 68gr OTM. I pulled the charging handle and the bolt locked on the round. The round appears to be catching on the feed ramps. My first thought was maybe I didn't have the mag seated all the way, so I tap the bottom of the mag and rack the charging handle again...same thing. I extract the mag from the magwel, cycle the charging handle a few times, tap the mag to seat all rounds to the rear, re-insert mag and cycle charging handle.....Same failure as before. This weapon always cycles fine at the range with Lake City 55grain. Any ideas???

Doc
Link Posted: 2/15/2006 9:43:30 PM EDT
Try another mag yet?
Link Posted: 2/15/2006 9:44:02 PM EDT
test your rifle completely with the ammo you will be using. maybe something about the 68's that chokes it. Better to find out on the range than when you really need it.
Link Posted: 2/15/2006 9:46:06 PM EDT
A malfunction with one mag is a huge problem?
Link Posted: 2/15/2006 9:46:49 PM EDT
With a bolt mounted charging handle you could have racked it back and rode it home.
Link Posted: 2/15/2006 9:49:57 PM EDT

Originally Posted By RaynoEleven:
test your rifle completely with the ammo you will be using. maybe something about the 68's that chokes it. Better to find out on the range than when you really need it.



I agree, that's why I considered this a huge problem. I'm thinking maybe a weak mag spring, so I guess I'll be changing mags. Need to get to the range asap and run a mag of this ammo through it just to make sure.
Link Posted: 2/15/2006 9:50:50 PM EDT
OTM + No M4 Feedramps
Link Posted: 2/15/2006 9:51:03 PM EDT

Originally Posted By Creeper:
With a bolt mounted charging handle you could have racked it back and rode it home.



Let's not turn this into an AR vs AK thread
Link Posted: 2/15/2006 9:54:48 PM EDT
Ok, now I'm convinced it's a weak mag spring, because when trying to unload the mag manually, the rounds were getting caught on the front of the mag body. Thanks everyone for the comments/suggestions, and I'll definitely be taking some of this ammo to the range with me next time.

Doc
Link Posted: 2/15/2006 9:57:06 PM EDT
My brownells mag has a little higher lip then the mil-spec ones I have. Might wanna check into that.
Link Posted: 2/15/2006 10:03:55 PM EDT

Originally Posted By Da_Bunny:
OTM + No M4 Feedramps



OK, now I'm thinking you're right. I just loaded up a brand new D&H teflon 30rnd and had the same thing happen. Got the gun cocked and locked with one in the chamber for now, but it looks like I'll either have to change my HD load, or Get some M4 feedramps.
Link Posted: 2/15/2006 10:08:27 PM EDT
also make sure the bullet tips aren't dragging on the front of the magazine.
Link Posted: 2/15/2006 10:11:46 PM EDT

Originally Posted By Bullseye_Doc_Holiday:

Originally Posted By Da_Bunny:
OTM + No M4 Feedramps



OK, now I'm thinking you're right. I just loaded up a brand new D&H teflon 30rnd and had the same thing happen. Got the gun cocked and locked with one in the chamber for now, but it looks like I'll either have to change my HD load, or Get some M4 feedramps.



I switched out to 68/75 gr OTM after I got the ramps on two carbines. No more problems.
Link Posted: 2/16/2006 4:49:24 AM EDT
what lower are you using?
what upper?
are you riding the bolt home?


i have never had any problems feeding 69 or 77gr rounds with no feedramps and if you look at it it points directly to the rifle feedramps which chambers fine.
Link Posted: 2/16/2006 5:12:48 AM EDT
Yes,

I agree it is a huge problem.
If there were real zombies, you'd be dead by now.

Get it fixed, or buy a new one. Now!
Link Posted: 2/16/2006 6:28:57 AM EDT
[Last Edit: 2/16/2006 6:30:14 AM EDT by Bullseye_Doc_Holiday]
Factory Bushmaster 16" HBAR 1:9 upper. LCW lower, RRA LPK, RRA 6POS.
Not riding the bolt home. Slingshot: pull CH all the way to the rear and let go.

MFingar: You're right it's a good thing there were no zombies

The reason this is such an issue, though, is that being that this is my HD AR, I keep a loaded mag in the magwell, but empty chamber and hammer down. In a HD situation, charging the weapon with the handle would be my means of redering it useful should I need to defend myself, and I don't need that step in the equation to mess up.

ETA: The gun is a little dirty, maybe I just have some carbon buildup I need to address, but I wouldn't think a little carbon would cause the gun not to chamber a round.
Link Posted: 2/16/2006 6:52:35 AM EDT
[Last Edit: 2/16/2006 6:54:11 AM EDT by Forest]

Originally Posted By Da_Bunny:
OTM + No M4 Feedramps



Not an issue. I run OTMs through my ARs and they don't have M4 feedramps. I've never had a problem with the OTMS.

Edited to add: Tighten the magazine catch 1 turn and see if it's still a problem for you.
Link Posted: 2/16/2006 6:55:23 AM EDT

Originally Posted By Da_Bunny:
OTM + No M4 Feedramps


BS. My 20" rifle does not have M4 feed ramps and feeds OTM just fine. There are no design differences in the relationship between the magazine feed lips, barrel extension, and chamber entrance between the M4 and the M16.

Just because your problem went away after putting in M4 ramps doesn't mean they are necessary. How do you know your barrel extension was just a little out of spec in the feed ramp area and cutting away more metal for the M4 ramps covered it up?
Link Posted: 2/16/2006 6:56:52 AM EDT

Originally Posted By Bullseye_Doc_Holiday:
Factory Bushmaster 16" HBAR 1:9 upper. LCW lower, RRA LPK, RRA 6POS.
Not riding the bolt home. Slingshot: pull CH all the way to the rear and let go.

MFingar: You're right it's a good thing there were no zombies

The reason this is such an issue, though, is that being that this is my HD AR, I keep a loaded mag in the magwell, but empty chamber and hammer down. In a HD situation, charging the weapon with the handle would be my means of redering it useful should I need to defend myself, and I don't need that step in the equation to mess up.

ETA: The gun is a little dirty, maybe I just have some carbon buildup I need to address, but I wouldn't think a little carbon would cause the gun not to chamber a round.


Try different magazines. The feed ramps are an aid to guiding the bullet in, but the bulk of the work of lining up the cartridge to go into the chamber is done by the magazine's feed lips.
Link Posted: 2/16/2006 7:10:22 AM EDT
AR 15s were chambering just fine decades before M4 feedramps.
Link Posted: 2/16/2006 8:50:37 AM EDT
Sure people, that's why Colt developed the M4 feedramps, because everything was just fine before that.

If you can shoot OTM without the ramps, great. In my experience, which is the only thing I can really go by, M4 feed ramps improved the performance of every rifle I put them on. Brand new Colt magazines that did not perform well in older rifles work just fine in M4 uppers, regardless of the lower.

You can call BS until you are blue in the face, it won't sway me one bit. It works.
Link Posted: 2/16/2006 8:55:11 AM EDT

Originally Posted By Da_Bunny:
Sure people, that's why Colt developed the M4 feedramps, because everything was just fine before that.



It helps to know the hows and whys.

M4 feedramps help feeding when you are dealing with the faster cyling rate of an M4 - as the spring (due to wear and/or dirt) may not feed the round up fast enough. Feed ramps definately IMPROVES reliability. On a clean gun just firing a few rounds they should make no difference.

We're not talking about a full-auto gun.

We're not discussing a dirty carbine, and hopefull worn magazines are not part of the problem.

But the fact remains for decades AR carbines have been feeding just fine w/o the ramps. If a clean rifle with decent magazines needs them for semi-auto fire - then that weapon has a problem.
Link Posted: 2/16/2006 9:05:13 AM EDT

Originally Posted By Forest:
Feed ramps definately IMPROVES reliability. On a clean gun just firing a few rounds they should make no difference.

We're not talking about a full-auto gun.

We're not discussing a dirty carbine, and hopefull worn magazines are not part of the problem.

But the fact remains for decades AR carbines have been feeding just fine w/o the ramps. If a clean rifle with decent magazines needs them for semi-auto fire - then that weapon has a problem.



Well, there you go. I don't build rifles to run under ideal conditions, I build them to run dirty with whatever is available. Every AR rifle I own, with one lousy exception, is a SHTF rifle.

The one exception is the 20" rifle I like to shoot 20 gauge shotgun shell hulls off a rock at 100 yards with. It has a M4 barrel extention and feedramps too.
Link Posted: 2/16/2006 9:19:27 AM EDT

Originally Posted By Forest:
But the fact remains for decades AR carbines have been feeding just fine w/o the ramps. If a clean rifle with decent magazines needs them for semi-auto fire - then that weapon has a problem.



Not 68gr OTM for decades, however.

OTM runs fine in all my AR's. However, on the FIRST round stripped from the mag, this does happen to me from time to time. The round hangs on the open tip, just on the adge of the upper receiver. Doesnt happen with ball.... and only happens on the first round stripped, never while firing. Happens on 45, 52, 68, and very rarely, my 77 HP's.

While M4 feedramps were NOT designed to fix this issue, it is still a potential issue, and I can easily see where a ramp in this location would make it a NON issue.

All my future builds will be using M4 ramps, if possible.
Link Posted: 2/16/2006 9:25:36 AM EDT
FOREST!!FOREST!!

Agree I have a Bushy A1 shorty with no stinking M4 ramps never evera hicup over 1000rds

STRANGE Bushy A1 20HBAR I got in 01 has m4 feed ramps from Bushy Factory !

I belive its for Full auto wich I dont have or need!
Link Posted: 2/16/2006 9:28:18 AM EDT

Originally Posted By FMJ:
Agree I have a Bushy A1 shorty with no stinking M4 ramps never evera hicup over 1000rds



1000 rounds of 68 OTM?

No? Oh, so that really has nothing to do with anything......
Link Posted: 2/16/2006 12:23:22 PM EDT

Originally Posted By Da_Bunny:
OTM + No M4 Feedramps



M4 feedramps..... I LOVE it.

God help the Millions of AR's out there without them !! When are we going to admit that this is a solution for a problem that ISN'T a problem with semi-automatic AR's.
Link Posted: 2/16/2006 12:27:55 PM EDT
My rifles don't have M4 feedramps, and they feed 68 gr. and 75 gr. OTM just fine.
Link Posted: 2/16/2006 3:51:25 PM EDT
Wow, this really turned into a shit storm. For all of you that don't see the need for M4 feedramps, good for you. Once again, for those of you that have a hard time reading the WHOLE thread:

Factory Assembled Bushmaster upper
All quality lower parts built on a Lauer lower
BRAND NEW D&H teflon 30 rounders w/green follower
I've put over 2000 rounds of m193 through this gun without the first hiccup...shitty range mags and all


There's obviously something this rifle doesn't like about the 68 grain OTM's. Some of you shared that your non-feedramped rifles also had issues feeding OTM ammo. I'm not going to dremel feedramps into this upper, but every other upper I build will have factory true M4 spec feedramps. As for those of you that haven't had problems feeding OTM rounds in your non-feedramped uppers, good for you. Keep shooting and enjoy every minute of it. We'll all need the practice for when the zombies really do come

Doc
Link Posted: 2/16/2006 9:57:38 PM EDT
My Oly 20" feeds 52gr OTM without issue. No feedramps. although I don't make a habit of using 30 round mags (20 rounders usually).

My Bushy 14.5" (SEBR) feeds 75gr OTM just fine with all mags (except for the bulging one). It does not have M4 feedramps.

So why would one factory rifle without feedramps be different than a homebuilt one? Sound like there is still something wrong with the placement of either the mag to the rifle ramps or something else it wrong. Ideally, there should be no difference as the bullets should stick straight into the ramps.

It sounds to me like the rounds are being presented to the barrel extension wrong.
Link Posted: 2/16/2006 11:03:17 PM EDT

Originally Posted By Bullseye_Doc_Holiday:
Wow, this really turned into a shit storm....but every other upper I build will have factory true M4 spec feedramps. As for those of you that haven't had problems feeding OTM rounds in your non-feedramped uppers, good for you.

Doc



You won't regret it when the problem that isn't a problem just goes away.
Link Posted: 2/16/2006 11:32:44 PM EDT
Link Posted: 2/17/2006 2:44:47 AM EDT

Originally Posted By Forest:

Originally Posted By Da_Bunny:
OTM + No M4 Feedramps



Not an issue. I run OTMs through my ARs and they don't have M4 feedramps. I've never had a problem with the OTMS.

Edited to add: Tighten the magazine catch 1 turn and see if it's still a problem for you.



+1. Thousands of OTMs in rifles without ramps and no feeding issues.
Link Posted: 2/17/2006 2:57:13 AM EDT
You said you did the slingshot method (pull charging handle all the way back and release it), did you try locking the bolt back then pressing the bolt release?
Link Posted: 2/17/2006 5:01:22 AM EDT
AMEN Troy!
Link Posted: 2/17/2006 5:17:48 AM EDT
The Winchester 45 gr varmint bullets would catch on my upper receiver. I only noticed this when I saw how scratched up the upper receiver was right under the rifle feedramps. I didn't get any major stoppages when I used good mags.
Link Posted: 2/17/2006 5:58:04 AM EDT

Originally Posted By Bullseye_Doc_Holiday:
Wow, this really turned into a shit storm. For all of you that don't see the need for M4 feedramps, good for you. Once again, for those of you that have a hard time reading the WHOLE thread:

Factory Assembled Bushmaster upper
All quality lower parts built on a Lauer lower
BRAND NEW D&H teflon 30 rounders w/green follower
I've put over 2000 rounds of m193 through this gun without the first hiccup...shitty range mags and all




As I said earlier doc first try to tighten the magazine castch. As you indicated the lower was not a factory build. Sometimes the catch can be a little loose and still feed FMJ, but not OTM.
Link Posted: 2/17/2006 6:49:57 AM EDT

Originally Posted By Troy:
Several things could cause this, including a bunch of tolerances that stacked the wrong way. Extending the feed ramps would probably solve the problem


You're not the first to mention that in this thread, but such advise was ignored because the rifle "feeds with FMJ".......

I wonder why people ask for help here, if all they do is discard sound advice because it doesn't fit their preconcieved notions.
Link Posted: 2/17/2006 6:50:04 AM EDT
I have had several of my work guns with burred locking lug ways on the barrel extension.

Feed 10 rounds manually and inspect the bullets. Realize that each side of the mag has a different slot it feeds through. If the rounds havbe gouges on the bullets (usually on opposite sides of the projectile) then you need to deburr the slots on for the lugs.

The typical symptom I had was the round half feeding, never making it to chambering.
Best of luck to you.
Link Posted: 2/17/2006 8:12:28 AM EDT
[Last Edit: 2/17/2006 8:15:20 AM EDT by SelectFire]
Val Kilmer avatar
I'm your Huckleberry sig line
how original...NOT
Link Posted: 2/17/2006 8:18:20 AM EDT
I probably don't know much, so I watch the designers.

When I did my homework on SPR rifles I read the military's SPR rifles were designed from the start to shoot Mk262 ammo and some rifles were built with extended feedramps. I decided I wasn't any smarter than they were and followed their thinking.
Link Posted: 2/17/2006 8:30:31 AM EDT
[Last Edit: 2/17/2006 8:31:23 AM EDT by SmallChange]

Originally Posted By Troy:
Several things could cause this, including a bunch of tolerances that stacked the wrong way. Extending the feed ramps would probably solve the problem.

What amazes me, though, is that anyone would keep a HD gun/ammo combo that THEY HADN'T THOROUGHLY TESTED. That's a good way to be killed.

-Troy



THANK YOU TROY!

Reading through this thread, I was starting to wonder if anyone was going to mention this or if I'd have to be the one. To me, this is the bigger issue than how he operated the charging handle or whether or not he has M4 feed ramps.

Hardware and techniques aside, don't ever put something into service as a home/personal defense weapon until you have made sure it will work.

You may feel that 68 OTM is a better home defense round than M193 -- but you know that M193 will go bang when you pull the trigger. THAT is what matters when the rubber hits the road.
Link Posted: 2/17/2006 9:59:30 AM EDT

Originally Posted By Bullseye_Doc_Holiday:

Originally Posted By Creeper:
With a bolt mounted charging handle you could have racked it back and rode it home.



Let's not turn this into an AR vs AK thread



Sorry- I'm a dick.
Link Posted: 2/17/2006 10:29:08 AM EDT

Originally Posted By SelectFire:
Val Kilmer avatar
I'm your Huckleberry sig line
how original...NOT


Link Posted: 2/17/2006 10:49:40 AM EDT
[Last Edit: 2/17/2006 10:50:40 AM EDT by Da_Bunny]

Originally Posted By twonami:

Originally Posted By SelectFire:
Val Kilmer avatar
I'm your Huckleberry sig line
how original...NOT





Seems like it's really the big issue here, don't it?

BTW, Val Kilmer would use extended feedramps. So would Chuck Norris.
Link Posted: 2/17/2006 11:36:55 AM EDT

Originally Posted By Da_Bunny:When I did my homework on SPR rifles I read the military's SPR rifles were designed from the start to shoot Mk262 ammo and some rifles were built with extended feedramps. I decided I wasn't any smarter than they were and followed their thinking.

If such M4 feedramps were necessary, don't you think that ALL SPRs would have them? By your own admission they do not.
Link Posted: 2/17/2006 2:16:09 PM EDT

Originally Posted By Da_Bunny:

Originally Posted By twonami:
Originally Posted By SelectFire:
Val Kilmer avatar
I'm your Huckleberry sig line
how original...NOT





I have gone by Glock Holiday with a Val Kilmer tombstone movie pic avatar and the same sig line for several years on no less than seven other boards.
Flame away if you want but it just pisses me off.
However I did send in my membership Today to support the board and post the correct avatar


Link Posted: 2/17/2006 2:19:02 PM EDT

Originally Posted By SWO_daddy:

Originally Posted By Troy:
Several things could cause this, including a bunch of tolerances that stacked the wrong way. Extending the feed ramps would probably solve the problem


You're not the first to mention that in this thread, but such advise was ignored because the rifle "feeds with FMJ".......

I wonder why people ask for help here, if all they do is discard sound advice because it doesn't fit their preconcieved notions.



Not discarding feedramp advice, If you'll notice I said I will have feedramps on all subsequent guns. Just not willing to put the money into it for this gun, not to mention most homemade feedramps are hack jobs because the barrel extensions aren't any longer. Then all you have is two dremmeled canyons in your receiver.

Link Posted: 2/17/2006 2:21:15 PM EDT

Originally Posted By Forest:

Originally Posted By Bullseye_Doc_Holiday:
Wow, this really turned into a shit storm. For all of you that don't see the need for M4 feedramps, good for you. Once again, for those of you that have a hard time reading the WHOLE thread:

Factory Assembled Bushmaster upper
All quality lower parts built on a Lauer lower
BRAND NEW D&H teflon 30 rounders w/green follower
I've put over 2000 rounds of m193 through this gun without the first hiccup...shitty range mags and all




As I said earlier doc first try to tighten the magazine castch. As you indicated the lower was not a factory build. Sometimes the catch can be a little loose and still feed FMJ, but not OTM.



Good advice. Sorry I missed it the first time. I just tightened the mag catch 2 turns. Still drops an empty mag free, and just cycled 28 rounds by hand without a hiccup.
Link Posted: 2/17/2006 2:25:58 PM EDT

Originally Posted By SelectFire:

Originally Posted By Da_Bunny:

Originally Posted By twonami:
Originally Posted By SelectFire:
Val Kilmer avatar
I'm your Huckleberry sig line
how original...NOT





I have gone by Glock Holiday with a Val Kilmer tombstone movie pic avatar and the same sig line for several years on no less than seven other boards.
Flame away if you want but it just pisses me off.
However I did send in my membership Today to support the board and post the correct avatar





Received your email and replied to you. Sorry dude, but I paid first so the avatar's mine

Besides, you can't claim to have any affiliation with Mr. Holiday because you're from Oklahoma. Doc was from GA, like me. Savannah to be exact. In fact, I think if Doc were here he'd tell you,

"You're no daisy, You're no daisy at all"
Link Posted: 2/17/2006 2:28:32 PM EDT
Colt instructors told me that the feed ramps were only designed to facilitate the more violent action of the 16" and shorter guns. On an SPR of 20" (or a GI M16) the action is slower, thereby eliminating the necessity for extended feed ramps and a true M4 upper receiver. The problems start when guys take a 20" upper from Colt and put on a short barell.

Again, that's not from me but from the Colt armorer course.
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