Diemaco SA Rifle Pics - post 'em here

Leg said:
Which is odd since the C7A2 and C8A3 do not have M4 feed ramps.
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I’ve thought about that, and the only reason I can come up with is that civilian rifles may be customized with lighter buffers or springs which would necessitate the m4 feed ramps to feed reliably. Military rifles will be issued with just the one tested buffer weight, making the feed ramps unnecessary
 
Leg said:
Which is odd since the C7A2 and C8A3 do not have M4 feed ramps.
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I thought it was odd as well. Till i got the explanation from cc.

Fuzzy Wool Hat said:
I’ve thought about that, and the only reason I can come up with is that civilian rifles may be customized with lighter buffers or springs which would necessitate the m4 feed ramps to feed reliably. Military rifles will be issued with just the one tested buffer weight, making the feed ramps unnecessary
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Not the buffers. The different grade of ammo and magazines. The mil rifles will only eat c77 or other nato spec ammo through one type of mag. Civvie rifles will run all variety of ammo from 50gr-77gr projectiles along with 223 and 556 cases. The changes in dimensions with m4 feed ramps enjures continued reliable feeding.

Since the c7/c8 have a gas system pretty much dialled around c77(along with some derivatives of c77) through the d&h mags the feed ramps don't do anything.
 
r34skyline said:
I thought it was odd as well. Till i got the explanation from cc.



Not the buffers. The different grade of ammo and magazines. The mil rifles will only eat c77 or other nato spec ammo through one type of mag. Civvie rifles will run all variety of ammo from 50gr-77gr projectiles along with 223 and 556 cases. The changes in dimensions with m4 feed ramps enjures continued reliable feeding.

Since the c7/c8 have a gas system pretty much dialled around c77(along with some derivatives of c77) through the d&h mags the feed ramps don't do anything.
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This
 
r34skyline said:
I thought it was odd as well. Till i got the explanation from cc.



Not the buffers. The different grade of ammo and magazines. The mil rifles will only eat c77 or other nato spec ammo through one type of mag. Civvie rifles will run all variety of ammo from 50gr-77gr projectiles along with 223 and 556 cases. The changes in dimensions with m4 feed ramps enjures continued reliable feeding.

Since the c7/c8 have a gas system pretty much dialled around c77(along with some derivatives of c77) through the d&h mags the feed ramps don't do anything.
Click to expand...

I call bull on that. US mil came out with the ramps and at the time they used same grade ammo and mags with M855. M4 ramps didn't come about because of commercial users using different mags/ammo.

Diemaco/Colt Canada have never found the ramps to be necessary and likely only offer them because end users ask for them.
 
Feed ramps did indeed come about due to feeding issues with the carbine gas system (M4) during full auto fire. Diemaco had solved the issue earlier with the HH buffer. Thus CC rifles and carbines don't "need" feed ramps. But as Leg points out commercial users and foreign sales asked for them.
 
jonesy67 said:
If you take a look at the original post, its a DD gas block. Just wondering, did you try to use the CC gas block under the rail? I tried putting the MRR barrel under a KAC URXII (20549) and it was just a bit to high. One other thing is why did you take the MRR out of its MLOK upper just to put an MLOK handguard on it?
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You are correct!

The OEM gas block is too high. That’s why I used a DD gas block.

I did this swap because now I don’t need a proprietary wrench to work on the rifle.
 
Leg said:
I call bull on that. US mil came out with the ramps and at the time they used same grade ammo and mags with M855. M4 ramps didn't come about because of commercial users using different mags/ammo.

Diemaco/Colt Canada have never found the ramps to be necessary and likely only offer them because end users ask for them.
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M4 also didn't use the hh buffer at the time. Once you use hh buffers with m855 you dont require the feed ramps. Mind you they don't hurt to have. Also keep in mind during early m4 years their gats had to feed both 855 and leftover 193. C77 was always used the 62 grain ss109 projectile. Hence why c77 doesn't have a green tip and m855 does.
 
The buffer has nothing to do with feeding. Any normal AR will work perfectly with an empty buffer or the old colt plastic spring guide - on semi. The buffer's only design purpose is to prevent bolt bounce back during high rate auto fire which causes light strikes. heavier barrels require heavier buffers because they make a bigger bounce - and the calculation must include attachments like a GL.

I used to teach armourer courses and prove it to students by letting them fire hundreds of rounds with an empty buffer from a C8A2 with no stoppages and then switch to auto and immediate light strike condition.

Some companies that lack engineering capability use heavy buffers to modify rate and bolt speed instead of tuning the gas port which is both correct and hard.

The only exception is very short barrel AR where the barrel is uncorked early and gas port tuning is not always sufficient. Then a larger buffer is introduced along with proper gas system.

Feed ramps were originally the result of poorly controlled magazine tolerances in USGI mag bodies. Canada used our own magazines (Thermold and later canadian metals mags) with very tightly controlled tolerances in the latch hole location. Ever notice that thermold had a rim that controlled how far up it would go?

Green tips were never for C77. Canada adopted the M16 system with 1/7 twist and only every had SS109 type 62 gr ammo. The US had old 55 gr and new 62 gr hence the green tip - they are not backwards compatible. 62 gr will not stabilize properly in a 1/9 or slower barrel - especially in colder or thicker air.

Feed ramps became more relevant with new commercial ammo and new NATO ammo with different profiles and larger meplats.
 
Matt K said:
The buffer has nothing to do with feeding. Any normal AR will work perfectly with an empty buffer or the old colt plastic spring guide - on semi. The buffer's only design purpose is to prevent bolt bounce back during high rate auto fire which causes light strikes. heavier barrels require heavier buffers because they make a bigger bounce - and the calculation must include attachments like a GL.

I used to teach armourer courses and prove it to students by letting them fire hundreds of rounds with an empty buffer from a C8A2 with no stoppages and then switch to auto and immediate light strike condition.

Some companies that lack engineering capability use heavy buffers to modify rate and bolt speed instead of tuning the gas port which is both correct and hard.

The only exception is very short barrel AR where the barrel is uncorked early and gas port tuning is not always sufficient. Then a larger buffer is introduced along with proper gas system.

Feed ramps were originally the result of poorly controlled magazine tolerances in USGI mag bodies. Canada used our own magazines (Thermold and later canadian metals mags) with very tightly controlled tolerances in the latch hole location. Ever notice that thermold had a rim that controlled how far up it would go?

Green tips were never for C77. Canada adopted the M16 system with 1/7 twist and only every had SS109 type 62 gr ammo. The US had old 55 gr and new 62 gr hence the green tip - they are not backwards compatible. 62 gr will not stabilize properly in a 1/9 or slower barrel - especially in colder or thicker air.

Feed ramps became more relevant with new commercial ammo and new NATO ammo with different profiles and larger meplats.
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-Best Armorer courses ever-
 
de36gl.jpg
 
CobraGT said:
Nothing super rare like some I've seen on here, but my MRR and SAS - I've wanted a B5 Sopmod stock for the SAS for a while, so also ordered a QD for the ACOG to go with it. Very happy with both of these. I've used the MRR a lot in training, but I think I'd like to run the SAS through its paces a bit more.

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This SAS looks awesome. Do you still having it?
 
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