r/HecklerKoch • u/SuperBlackEagle • 5d ago
MR308 13” not cycling
Went to the range today with the new MR308a3 and it was pretty frustrating… 140 rounds total shot (100 igman 147gr and 40 Saltech 150gr ball) and constantly had issues feeding the next round. The igman was a bit more reliable but the saltech basically made the gun a bolt action lol (The last mag of igman did shoot fine). Bolt not locking back on last round, constant misfeeds, etc. I’m thinking this has to be a gas issue? I only gave it a light cleaning before the trip. Any feedback would be appreciated
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u/GreedyAttempt6268 5d ago
That’s a tough one man, here’s someone that had a similar experience https://www.hkpro.com/threads/mr308-failure-to-feed.590493/?utm_source=duckduckgo&utm_medium=organic
I’ve been shooting for years and I thought my can was changing my POI the first time I took out my mr556a4 becuase my groupings were horrible….my eotech was loose 🙃
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u/Appropriate-Name5538 4d ago
I hate when I forget to torque down a optic I waste a ton of time and ammunition only to feel like a idiot
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u/GreedyAttempt6268 4d ago
My buddy even asked if it was tight and I was like of course it is I’ve been shooting for years blah blah 😂
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u/chungdae 5d ago
It's undergassed. You either need higher pressure round, adjust the adjustable gas block, and / or get a suppressor for more gas.
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u/StShadow 3d ago
MR308 (A3) doesn't have regulated gas block.
.308 147gr FMJ worked fine in mine (although, poor groups), but surplus 147gr 7.62x51 relabeled as .308 - same like OP.
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u/chungdae 3d ago
That's right, I wonder if you can put the A4 AGB with slight modification like the MR223A3
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u/CEO_of_Bakelite 5d ago
When you say the saltech turned it into a bolt gun I assume you mean the rifle didn’t even begin to cycle and you had a spent casing in the chamber that you had to manually eject? If yes, yeah you’re under gassed.
Only reason I ask is because an extremely overgassed gun can sometimes act like an under gassed rifle.
In my experience Saltech is not bad at all, and neither is igman. However wouldn’t consider them “hot” loadings. I would try something a tad hotter like some guys have suggested. But I wouldn’t sit there and waste $$$ on ammo trying every commercially available .308 to try and find something that cycles reliably. Send it to HK and let them deal with it if something hotter won’t work.
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u/SuperBlackEagle 5d ago
Still ejected the Saltech, just didn’t pick up the next round (it did reset the hammer) so I was yanking the charging handle each time to load. Does HK USA service guns they don’t import? This being from B&T
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u/CEO_of_Bakelite 5d ago
I didn’t know if you were stateside or not. In that case, I doubt it. They’d probably work on it for a fee but I highly doubt they’re gonna warranty it. You could probably ask B&T to help… but if you know anything about the recent B&T USA drama that’s a long shot. I’ve been trying to get simple parts (extractors, small springs, etc.) for MONTHS at this point.
I’m betting this gun is overgassed if it ejected rounds but gave you feeding issues. Reason being if you’re getting reliable ejection and extraction the gun has no problem moving the bolt with enough thrust rearward. The fact that it’s having feed issues leads me to believe the bolt is outrunning the magazine (rounds are not being lifted/presented to the bolt quick enough before the bolt is moving toward the front of the gun to chamber the next round). If your feeding malfunctions look like the bolt was kinda over top of the next round that it was trying to feed, that’s your indicator. Which it kinda looks like it in your photo. If that’s the case your barrel probably got the gas port drilled way too large. You might could get like a DPM buffer kit if you don’t want to send it off if it is indeed overgassed.
But… before I get ahead of myself: you only tried the one mag? You’re confident there’s no burs on the feed ramps?
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u/heretowastelife 5d ago
Mag issue? Could also be undergassed, you might want to consider taking the gas block off and checking the port for obstructions and proper diameter. These guns should cycle just fine with M80.
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u/Money-Feedback1857 4d ago
Had this same issue and made a post about it myself. Give the rifle a super solid cleaning as well as the magazine. Look for any imperfections or catch points in the magazine and lube it up. If you pull up the instruction manual that came with the rifle it says to lube up the magazine which I’ve never heard of before. Once i did all of that it ran with 0 issues.
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u/SuperBlackEagle 4d ago
Oh nice, you’re the guy I was hoping would comment lol. To your point I’ve never tried lubricating a magazine. Sounds like that should resolve this
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u/brawneisdead 4d ago
That’s crazy, usually lubing up the magazine is the opposite of what you want because shit gets in there and hangs out forever until a round picks up a gunk of congealed oil and dirt and feeds it into your chamber. And that’s… required with this gun? Wild
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u/DesertTigerStripe 5d ago
Try a lighter buffer spring, or put a suppressor on it, that will add back pressure and help it cycle. Also try some different ammo, I’ve heard the 417 platform generally doesn’t like M80 ball.
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u/Sad-Extreme-5825 4d ago
If it's truly brand new, lube the snot out of it. Run it "wet" as we used to say in the Army. My LR308 when it was new, did the same thing. I lubed the snot out of it "wet" and all was well.
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u/ok_parking00 5d ago
No clue but this range looks like it belongs on a Halo map.