Gaujo
UZI Talk Supporter
This thing gets a M11/9 to about 650 rof without impacting the back plate and perfect function. It doesn't matter if the spring fully compresses or not
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CF-W9mmA Bolts Coming Soon...
- Thread starter MACsAlot
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UZI Talk Supporter
This thing gets a M11/9 to about 650 rof without impacting the back plate and perfect function. It doesn't matter if the spring fully compresses or not
ScangaNation
Member
I’d buy one!
ScangaNation
Member
I’d love to buy and “og” new bolt to add to the collection
Probably like this. This is the bolt and spring I received recently. It’s supposed to be set up for an M11/9. You can see the spring compresses completely before the bolt bottoms out on the back of the receiver.
Based on comments from Vegas SMG here and in other threads, I don’t think this is supposed to happen like that.
I haven’t had a chance to start messing with clipping coils just yet. For the time being, I just started adding buffers until the bolt bottoms out on those before the spring goes solid.
I’m not sure if my bolt was assembled with the wrong spring or not. Not having another to compare to, I couldn’t say for sure.
What I was hoping for was a smooth recoil impulse where the bolt does not impact the receiver at the rear, but that hasn’t been the case. And cutting coils would not fix that. Maybe a slightly stronger spring to start with, then clip coils to tune? But as noted, I haven’t had a chance to mess with it much.
I talked with Sam yesterday and he mentioned he was shipping recoils springs with more coils than Tom recommended so the owners could tune the system to their desires.
If the bolt is bottoming out on the spring, I think it's time to cut some coils. The bolt should not bottom out on the recoil spring.
With my previous testing, 9x19 (9mm) and 9x17 (.380) there needs to be two different length recoil springs and rods.
65-63 coils on the recoil spring for .380 on the M11A1 frame. I found 63 coils to be the best.
90+ coils on the spring for 9x 19 ammo on the M11A1 frame.
*Using the 65-63 coil recoil spring with 9x19 ammo could cause damage to the lower receiver of the M11A1 and M11/9.
If the bolt is bottoming out on the spring, I think it's time to cut some coils. The bolt should not bottom out on the recoil spring.
With my previous testing, 9x19 (9mm) and 9x17 (.380) there needs to be two different length recoil springs and rods.
65-63 coils on the recoil spring for .380 on the M11A1 frame. I found 63 coils to be the best.
90+ coils on the spring for 9x 19 ammo on the M11A1 frame.
*Using the 65-63 coil recoil spring with 9x19 ammo could cause damage to the lower receiver of the M11A1 and M11/9.
... unless by clipping coils to the point where the spring does not go solid, we gain around 1/2” of additional bolt travel, which can have a significant effect on ROF.
Hmmm. Need to get out and mess with this thing...
And I should probably buy a couple more springs for when I mess up this one.
A&S Conversions
UZI Talk Life Member
As the same with the bolts Tom shipped, every gun can be a little different. Some have a little more drag than others. There is also ROF. Some might find the absolute slowest ROF to be "choppy". So bolts are shipped with a spring with the number of coils to be sure that even a gun with some extra drag will run. It would be up to the buyer to adjust the number of coils they wish to run. That is why the paperclip mod was on the bolt as shipped. The new owner would adjust the number of coils they wanted then install the permanent roll pin.
Scott
boomer535
Well-known member
Here is a link to my Son shooting our M11/9 with an original CFW-9MM bolt with a shockwave 50 round magazine.
https://youtu.be/nwTYLIOO4PA
https://youtu.be/nwTYLIOO4PA
Vegas SMG
UZI Talk Life Member,
Direct from Practical Solutions.
Start by clipping five coils and work from there. You’ll drop about 100 RPM. As you know, ammo matters.sometimes a lot.
Ok, some info on the M11/9. But I'm scratching my head over it a bit.
I started by using the spring that came with the CF-W9mmA bolt. As received, the spring was too long. It would go solid before the bolt would bottom out on the back of the receiver. This can be pretty hard on the spring, not to mention all of the force that's transferred through the op rod to the back of the receiver when the bolt doesn't hit the buffer. Here's how much space remained between the rear of the bolt and the buffer when the spring was fully compressed.
I had to add 1/2" of buffer to the rear to get the bolt to bottom out before the spring did. So I went to the range with the gun set up in this manner, with the intention to measure the ROF, then start cutting coils.
The spring that had come with the bolt had 107 coils. I also got a couple of replacement springs, courtesy of Strobro32 (thanks!) One of these also had 107 coils, and the other had 117. From what he had posted previously, the "orange" springs are what Sam at PS supplies with the bolts, and are not the same as standard M11/9 springs. My 107 coil spring was around a half inch shorter than the one Strobro sent. But then I may have caused a set to the spring when I initially shot it without the extra buffers in place.
I was shooting 10-round bursts for all measurements. Ammo was 115 gr. FMJ reloads, using 5.0 gr. HP-38 and WSR primers (ran out of pistol primers a while ago). These average 1276 fps. from the MAX-31. I haven't chrono'ed them through the stock M11/9 barrel.
Set up with the extra buffers and shooting the 115 gr. ammo, I got 740 RPM.
I then removed the extra buffers and cut the spring to where the bolt would bottom out on the one buffer just before the spring would have gone solid. That put me at 94 coils. With a shortened spring and a lengthened bolt stroke, the gun should run slower, right? Interestingly enough, I got 831 RPM this time.
I then started cutting coils and testing some more. I had also brought some 124 gr. Winchester 9mm NATO ammo, although I missed testing it on the first couple of runs before cutting coils. Results as shown below:
115 gr. FMJ
Spring Coils-----ROF
107 (1/2" buffer)--740
94------------------831
86------------------661
81------------------697
90 (new spring)---667
At 81 coils, the guide rod was slightly longer than the uncompressed spring. Also, I had a couple of the rifle primers fail to ignite. It also started to run a bit inconsistent. I ran three 10-round tests. The results were 740, 600, 750, giving the average of 697.
Also of note, at 81 coils the ROF was actually faster than at 86 coils. I ran three tests at that spring length as well and they were a consistent 659, 659, 667. I think the shorter spring is now allowing the bolt to slam back harder, rebounding off the rear of the receiver, and actually speeding up the bolt return.
In the end, I cut one of the new springs at 90 coils. It gave 667 RPM.
I also tried the 9mm NATO ammo. Results were:
Spring Coils-----ROF
86------------------725
81------------------788
90 (new spring)---692
Again, the original spring at 81 coils was faster than at 86 coils. And the new spring at 90 coils was slower than both.
The ideal setup will have the spring tension such that the bolt slows and stops just before hitting the rear of the receiver. This makes for a slow, smooth feeling subgun. I suspect the 90-coil spring is doing this, although I wasn't really paying attention to how the gun felt when I was shooting.
I'll have to get out and play with it some more. I also need to try some 147 gr. ammo and see how it feels/runs before I settle on a final spring weight.
I started by using the spring that came with the CF-W9mmA bolt. As received, the spring was too long. It would go solid before the bolt would bottom out on the back of the receiver. This can be pretty hard on the spring, not to mention all of the force that's transferred through the op rod to the back of the receiver when the bolt doesn't hit the buffer. Here's how much space remained between the rear of the bolt and the buffer when the spring was fully compressed.
I had to add 1/2" of buffer to the rear to get the bolt to bottom out before the spring did. So I went to the range with the gun set up in this manner, with the intention to measure the ROF, then start cutting coils.
The spring that had come with the bolt had 107 coils. I also got a couple of replacement springs, courtesy of Strobro32 (thanks!) One of these also had 107 coils, and the other had 117. From what he had posted previously, the "orange" springs are what Sam at PS supplies with the bolts, and are not the same as standard M11/9 springs. My 107 coil spring was around a half inch shorter than the one Strobro sent. But then I may have caused a set to the spring when I initially shot it without the extra buffers in place.
I was shooting 10-round bursts for all measurements. Ammo was 115 gr. FMJ reloads, using 5.0 gr. HP-38 and WSR primers (ran out of pistol primers a while ago). These average 1276 fps. from the MAX-31. I haven't chrono'ed them through the stock M11/9 barrel.
Set up with the extra buffers and shooting the 115 gr. ammo, I got 740 RPM.
I then removed the extra buffers and cut the spring to where the bolt would bottom out on the one buffer just before the spring would have gone solid. That put me at 94 coils. With a shortened spring and a lengthened bolt stroke, the gun should run slower, right? Interestingly enough, I got 831 RPM this time.
I then started cutting coils and testing some more. I had also brought some 124 gr. Winchester 9mm NATO ammo, although I missed testing it on the first couple of runs before cutting coils. Results as shown below:
115 gr. FMJ
Spring Coils-----ROF
107 (1/2" buffer)--740
94------------------831
86------------------661
81------------------697
90 (new spring)---667
At 81 coils, the guide rod was slightly longer than the uncompressed spring. Also, I had a couple of the rifle primers fail to ignite. It also started to run a bit inconsistent. I ran three 10-round tests. The results were 740, 600, 750, giving the average of 697.
Also of note, at 81 coils the ROF was actually faster than at 86 coils. I ran three tests at that spring length as well and they were a consistent 659, 659, 667. I think the shorter spring is now allowing the bolt to slam back harder, rebounding off the rear of the receiver, and actually speeding up the bolt return.
In the end, I cut one of the new springs at 90 coils. It gave 667 RPM.
I also tried the 9mm NATO ammo. Results were:
Spring Coils-----ROF
86------------------725
81------------------788
90 (new spring)---692
Again, the original spring at 81 coils was faster than at 86 coils. And the new spring at 90 coils was slower than both.
The ideal setup will have the spring tension such that the bolt slows and stops just before hitting the rear of the receiver. This makes for a slow, smooth feeling subgun. I suspect the 90-coil spring is doing this, although I wasn't really paying attention to how the gun felt when I was shooting.
I'll have to get out and play with it some more. I also need to try some 147 gr. ammo and see how it feels/runs before I settle on a final spring weight.
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