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Discussion Starter #1
Hey all,

Just wondering if there are some ways to increase the ROF on an MP5. Right now it is running at around 600 rounds per minute. Any way to bump it up to 700-800? Maybe a different locking piece, new recoil spring, etc.? Thanks in advance!
 

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I don't think it's a good idea but if you change the diameter of roller (-) you will increase the rpm.
 

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I don't think it's a good idea but if you change the diameter of roller (-) you will increase the rpm.
You will also change your bolt gap, which is not a good idea unless you are already out of tolerance. A different locking piece could help, as could a different recoil spring. Can you tell which locking piece you have now? 600 rpm seems pretty slow for an MP5. Do you have video?
 

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The standard MP5 should be running in the 700 range if the right LP/rollers/spring are all correct. The K guns run a bit faster, getting up into the 850-900 range.
 

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Discussion Starter #9
Wolf Performance Ammo, 115 grain. Would a heavier grain/more powerfully loaded round result in more energy transfer to the bolt carrier, resulting in a faster rate?
 

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That video doesn't sound like 600rpm to me...maybe a tad faster than that. I run S&B 115 - standard stuff - in my clones and they run fast. It's good, inexpensive ammo. I've shot probably 20K rounds and not had a single fail of any rounds.
 

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If the K carrier worked, the only way i see that helping ROF is a little less mass, but id be concerned about fitment more so.

Try a hotter loaded ammo. A good 124gr round should bump the ROF up a tad. The video does sound closer to 650-700rpm as well
 

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Discussion Starter #14
Just an estimate. Most of the MP5s I've seen fired noticeably faster. I'm sure it's the standard locking piece and I don't have the tool to measure bolt gap.
 

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leib, son... you need to spend the cost of a Big Mac and get a set of feeler gages... seriously. Next step is to find someone with a Pact Timer to actually find out exactly what RPM you're running. I have one here, but I'm a bit of a drive for you... and sadly, I no longer loan stuff out. Somebody decided they didn't need me as a friend anymore and took off to other AO's with some of my tools. I hate buying things twice.
 

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leib, son... you need to spend the cost of a Big Mac and get a set of feeler gages... seriously. Next step is to find someone with a Pact Timer to actually find out exactly what RPM you're running. I have one here, but I'm a bit of a drive for you... and sadly, I no longer loan stuff out. Somebody decided they didn't need me as a friend anymore and took off to other AO's with some of my tools. I hate buying things twice.
I hate buying things twice too, especially when it's just cause I can't remember where I put the first one. And what is even worse than that is when I don't even remember buying the first one. Then later I'm digging through a box and BAM, I didn't even know I already had one of those.

Yeah, I'm getting old.
 

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Change to a K carrier, check the gap and adjust as necessary and it will run like a Baptist from a camera at a bar! Less mass................its a another class. Been there and still there............done it and it works.
 

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A firearm is a system. If you want a fast running MP5 style of gun, just get a MP5K clone. The barrel is shorter so there is less of an impulse from the round. The receiver is 3/4" shorter and the bolt group is shorter so it does need to move as far to cycle. So it takes less time to cycle. So the cyclic rate is is higher. To make the cyclic rate higher, the carrier in the standard MP5 would need to be accelerated or lightened. The problem is, if the carrier moves faster, it will hit the back end of the receiver hard and cause damage. So the spring resistance would need to increase. But that would decrease the cyclic rate. So you are back to the slower cyclic rate, maybe. I'm not a firearms designer, but it would be difficult to safely change the cyclic system.

I've got a reverse stretch. The cyclic rate is a little higher than my full size. It has a K carrier in a full size receiver, so the carrier is lighter, but it goes further in a full size receiver. My K cycles faster, but I've still been able to get singles out of it, but it does take a little more effort. To me the easiest thing to do for higher cyclic rate is get a K clone. YMMV.

Scott
 
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