FTE with ARMS 18 on M305S

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I took my new new shorty out to shoot and had a lot of issues with FTEs with my ARMS18 mount. With some older winchester .308 I had it jam more than 50% of the time. Basically the casing is getting jammed between the ring and the oprod handle.

Has anyone seen this before? Also, I shot 10 rounds of hornady ammo with no jams.

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This issue has been covered lots of times on here and it is a well-known issue with that particular mount. Some have milled out a part of the mount while others have taken the less extreme measure of fixing the ejector. Search function for all the details.
 
i was too lazy to mod mine to work, so i just bought a Sadlak Airborne mount instead. its just a much, much nicer mount in general than the arms18
 
Modifying the ejector is the easiest way to fix that issue. I have the same issue with mine, and instead of screwing around with the Norinco spring I just ordered a USGI replacement ejector spring. I've heard this fixes the problem for most people, and it cost me less than $15. I think people need to consider why they are buying the ARMS and be prepared to have this issue and fix it. You buy the ARMS to have the lowest mount possible, allowing use of the iron sights and a better cheek weld for optics. If these things are not as important to you, there are other very good mounts to invest in, like the Sadlak.
 
Silent8Strike said:
Modifying the ejector is the easiest way to fix that issue. I have the same issue with mine, and instead of screwing around with the Norinco spring I just ordered a USGI replacement ejector spring. I've heard this fixes the problem for most people, and it cost me less than $15. I think people need to consider why they are buying the ARMS and be prepared to have this issue and fix it. You buy the ARMS to have the lowest mount possible, allowing use of the iron sights and a better cheek weld for optics. If these things are not as important to you, there are other very good mounts to invest in, like the Sadlak.
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Ditto
FTE's are very common with the new style ARMS 18. I used a TA70, a touch higher and better eye relief. No more FTE's or stovepipes.
 
shooterman said:
Ditto
FTE's are very common with the new style ARMS 18. I used a TA70, a touch higher and better eye relief. No more FTE's or stovepipes.
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Yepper!
If your not a garage gun smith then go with smith or sadlak but steer clear of the aluminum mounts. Over time and use they do fail.
 
I've installed many smith enterprises mounts that do the same thing. it's not just an arms 18 thing.
many times it's the rings themselves, well the forward one. but often times, especially on Chinese rifles, the extractor and ejector springs are over length and too strong. creating an unfavorable ejection path
trimming the springs to G.I. length or replacing with US made m1a springs and careful selection of rings, has solved the arms 18 issue on a great many of these rifles. still my go to mount ;)
I have real live video of the smith enterprise mount jamming brass between it and the oprod so it isn't just an arms 18 thing.
 
I use the ARMS 18 mount. I get just what you picture. Trimming Norc springs helped. A USGI bolt and guts made it worse. Took a cutting disc and cut out the right side of the mount between the two ends where I put the rings. Helped but didn't solve. Put it on a different rifle. Still had problems. Finally screwed a metal tab to the side of the front ring so that hangs down in the area that the shell case jams. That has helped so that a jam is quicker to clear.
 
You could also try flipping the ring around so the QD lever is on the other side. That might give you more room on the ejection port side.

Shawn
 
I am having an issue with ejection on my M305 at the moment, the rifle is spitting spent brass almost straight forward and occasionally they ding off my brand new leupold scout scope (one case already put a slight nick in the ocular lens ...F&%K). anyone care to suggest a fix? It is a Norc bolt but contains a usgi ejector and wolff springs. Would chopping a couple coils off the ejector spring help to prevent this in the future? when performing this, how much is too much?
 
shawn said:
You could also try flipping the ring around so the QD lever is on the other side. That might give you more room on the ejection port side.
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Yeah, I bought it used and they had mounted it like that. It's pretty silly as the levers interfere with the oprod handle in forward and rear position and with the scope adjustment cover.
Regardless, it wouldn't help with the original issue.
 
I had the same problem with my leapers aluminum mount until I reversed the rings, now it doesn't jam. You'll notice on the bottom of the mount all the little dings that are made from the brass hitting the roof, you can try filing that a bit. I'm just saying you can do it, I haven't tried with mine yet but I will.
 
Scart said:
Yeah, I bought it used and they had mounted it like that. It's pretty silly as the levers interfere with the oprod handle in forward and rear position and with the scope adjustment cover.
Regardless, it wouldn't help with the original issue.
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How do you know? Have you tried it? Often the simplest explination is the correct one.

Shawn
 
2 coils of extractor spring iF it's over length. Check the online resources that exhist for USGI extractor and ejector spring free length and if availlable NM length.

Most wolfe hammer, ejector and extractor springs are over length and need to be correctly fitted. Most guys just drop em in and think they've done an upgrade when really, no upgrade has occurred hehehe.

Making the 2 coils off extractor, 3 coils off ejector springs has shown , at least with chinese springs, to alter the ejection path more to the rear. Ideally they should go out and back slightly.
 
Do make sure you know what the USGI or NM free lenght is before trimming your springs. And then, only take off one coil at a time if possible.

An underpowered or too short ejector spring can result in a self disassembling bolt.

Ask me how I know...
 
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Charlemagne70 said:
Do make sure you know what the USGI or NM free lenght is before trimming your springs. And then, only take off one coil at a time if possible.

An underpowered or too short ejector spring can result in a self disassembling bolt.

Ask me how I know...
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LOL!!!
Bolt separation...
Sounds so bad :p
 
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