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Discussion Starter · #1 · (Edited)
Hi all,

Thanks for the add.
I recently acquired a C308 and so far am in love!
I hope to add some more HK roller lock design clones to the arsenal.

I have a couple questions.

I'd like to add a green grip to match the furniture I installed.
I know I will need a steel clipped and pinned lower.
My question is, will the trigger pack from the C308 drop in to the steel lower, or would I need to get a different trigger pack as well? I asked RTG and they said "Only if the trigger pack is an HK trigger pack. A Cetme trigger pack will not function properly in an HK style lower." -- IDK what kind of trigger comes in the C308 though.


Next item: I'd like to install a heavy buffer to tame the recoil a little.
Do I need to purchase any additional parts other than the buffer itself? (ie: different spring, hardware, etc.) Or can I use what's already in the rifle?


Any other worthwhile practical upgrades and/or ideas very welcome.


And now for a pic.
Rocking an SWFA SS 1-4x24IR.
 

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I have not handled one of these new Cetmes made on the PTR receiver, but from what I have read the lower including the FCG is also made up of new PTR US made parts (PTR91 HK style FCG). If you remove the FCG from the lower and post a photo we would be able to tell you which FCG you have in your rifle. If so all you will need is a clipped and pined steel lower and the safety selector lever for the steel lower (when you buy a lower they generally come with the proper selector lever). Also RTG has POF clipped and pinned OD green plastic lowers which should work with the selector you have. I think you can also put an actual Cetme FCG in an HK lower or vice versa but the safe and fire positons are reversed. I know for sure that you can swap entire lowers between the Cetme and HK91.

HK Green Plastic SEF Clipped & Pinned Lower, Semi-Auto, HK91 HK93, HK94 MP5 Semi, Contoured Grip, HKK-5446, RTG Parts

You should check out militaryfirearms.com and become a member. It used to be the Cetme forum and there is a ton of knowledge about Cetmes over there. They can also help you do all the proper checks to make sure everything is in spec including bolt gap and cocking tube gap.

Militaryfirearm

As far as the heavy recoil buffer I recommend either a PCS heavy buffer or a Bill Springfield Improved G3 buffer kit. Both of these options are very affordable and work well.
The Bill Springfield conversion Kit consists of a new piston and spring for your existing HK buffer (I assume you have a G3 buffer in your HK stock set?) and costs only $39 shipped. This is an easy job that you can do your self in a half an hour or less with hand tools and no modifications to the stock are required (this is a great option for wood stocks because you only change the internals of the buffer).

Bill Springfield - www.TriggerWork.net

The PCS heavy buffer is made by Gilliebear and costs $64.95 at RTG. The PCS heavy buffer is really nice and is a drop in unit with no modifications required on a plastic HK stock. It is approximately twice as long as a standard buffer but has the same outside diameter so it fits in the housing fine (for a wood stock you would need to make the buffer hole deeper).

HK Heay Buffer, U.S. PCS, HK91, G3, PTR91, HK33, Parabellum Combat Systems, HKK-1989, RTG Parts

An HK heavy buffer can be used but they are approximately twice as long as a standard buffer and the outside diameter is larger than the standard buffer so the buffer hole would have to be enlarged. These are great and I have a couple of them but they are very expensive and require modifications to the stock. The HK MSG90 buffer is also great and I have one of those too but again they are expensive. Again they are approximately twice as long as a standard buffer but these have the same outside diameter as the standard buffer so no modifications are needed for a plastic HK stock.

At the time I bought the buffers for my rifles the PCS heavy buffer and the Bill Springfield HK buffer improvement kit were not being produced yet. If they had been on the market at the time I would have bought them instead of my Heavy HK buffers and my HKMSG90 buffer.

I would also recommend the following:

1) An HK21 style Buttpad they are wider and made of rubber. they make shooting one of these rifles much more comfortable. HK21 Rubber Buttpad New $39.95, HK G3, HK91, PTR91, HK33, HKK-1525, RTG Parts

2) and 3) A wide Green POF forearm (when back in stock). These provide a much better grip and do not heat up as quickly. Also they have the attachment point for the HK style light bipod which I also recommend.

HK G3 Green Wide Handgaurd New, HK91, PTR91, HKK-2015, RTG Parts

HK Bipod for HK91 G3 HK93 HK33 PTR91, Wide Handguard Mounted Light Steel Bipod, HKK-1185, RTG PARTS

4) I recommend getting a trigger job. Williams trigger specialties is my favorite for HK trigger work but Bill Springfield also does good work. Both of these are affordable, with a very quick turn around time and a trigger job will make the rifle a joy to shoot and greatly improve your groups. I think they both charge about $65 dollars to get about a 5 to 6 pound trigger pull.

Standard

Bill Springfield - www.TriggerWork.net
 

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Wow great info!
Lots to consider, thank you!

Here is the FCG:

While someone here can probably ID the FCG like that, I believe he meant for you to remove it from the lower and send a pic of it that way.

Though now that I think about it, as it has "safe" up and "fire" down that should be an HK style FCG and not a CETME.
 

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Wow great info!
Lots to consider, thank you!

Here is the FCG:

If you rotate the selector lever all the way to the top you should be able to pull it out of the lower (push it out from the right side to the left). Then you can remove the fire control group from the lower. Please do that and post some photos so we can get a better look at which fire control group your rifle has.



I also found a PDF from RTG of HK Cetme parts compatibility:

View attachment CETME-HK-G3-Compatibility.zip
 

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It's obvious the FCG is CETME.
What I'd like to see pics of would be the selector. It seems as though the selector shaft was modded to allow the SAFE position to be at the top like HK, unlike the traditional CETME FCG which has the FIRE position at the top.

If so, judging by a photo I found on the web, it looks as though the selector lever has been tack welded to the shaft. Just wondering if this is a hybrid selector that will only work with the C308 trigger group or if other mods have been made internally. At this point it doesn't seem possible that an original CETME selector would work with this FCG.

Any other worthwhile practical upgrades and/or ideas very welcome.
If you want a steel lower so you can add a green grip I would consider swapping out the complete lower and FCG to HK.
The reason being is that if your FCG was put into an original steel clipped/pinned CETME lower housing, the SAFE position that is marked on the housing would be the FIRE position in your FCG.....from a safety standpoint, I don't think that's a good idea.



Auto part Metal
 

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It's obvious the FCG is CETME.
What I'd like to see pics of would be the selector. It seems as though the selector shaft was modded to allow the SAFE position to be at the top like HK, unlike the traditional CETME FCG which has the FIRE position at the top.

If so, judging by a photo I found on the web, it looks as though the selector lever has been tack welded to the shaft. Just wondering if this is a hybrid selector that will only work with the C308 trigger group or if other mods have been made internally. At this point it doesn't seem possible that an original CETME selector would work with this FCG.


If you want a steel lower so you can add a green grip I would consider swapping out the complete lower and FCG to HK.
The reason being is that if your FCG was put into an original steel clipped/pinned CETME lower housing, the SAFE position that is marked on the housing would be the FIRE position in your FCG.....from a safety standpoint, I don't think that's a good idea.



View attachment 94802
I agree with basically everything 21HK said. However I am almost positive that the lower is a standard PTR 91 lower if so you should be able to use the Cetme fire control group and your C308 selector in the POF OD Green plastic lower that I told you about.

Please do post a photo of the selector if they just modified it then I agree that it might not be a great idea to put it in a steel HK lower because it would read safe when it was in the fire positon (this is because changing from a plastic to a steel lower requires a different selector). However if they only modified the selector and not the pack you could just use a steel Cetme lower with the proper selector. They are harder to find but should not be expensive and you could get it clipped and pinned for a reasonable price. The steel Cetme lowers take the same pistol grips as the steel HK lowers. This option should be much less expensive than buying an entire semi HK group and clipped and pinned lower.

Steel Cetme lower:

http://www.gunpartscorp.com/Products/1528490.htm
 

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Thanks for taking time to post the pics of the selector. It's definitely cut different than the original CETME and for comparison I added an HK, both are for the steel lowers.

Product
 

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So, will my FCG work in an HK or CETME lower?
Please excuse my ignorance -- I'm new to this system.
Yes it will fit and function in either an HK or Cetme lower. However a metal lower (either HK or Cetme) would require a different selector. If you use a plastic HK lower (like the Green one at RTG that I posted for you) you could use your Cetme FCG and the selector that came in your Cetme and it should function fine. With that set up the selector would also read safe and fire at the proper location just like it is in the lower you have now.

If you put your FCG in a steel HK lower you will have to change the selector to make it work. Then it would read fire when it was on safe and safe when it was on fire (unless you could get someone to modify a selector for a steel lower the way that 21Hk observed that your selector has been modified).

A third option is to put your FCG in an original steel Cetme lower (it would need to be clipped and pinned) and use the proper selector for that lower. It would then function correctly. However the safe and fire positions would be reversed which is the way that they were on original Cetmes. The steel Cetme lower looks almost the same as the steel HK lower but has different markings. It takes the same grips a steel HK lower.
 

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Discussion Starter · #17 ·
Yes it will fit and function in either an HK or Cetme lower. However a metal lower (either HK or Cetme) would require a different selector. If you use a plastic HK lower (like the Green one at RTG that I posted for you) you could use your Cetme FCG and the selector that came in your Cetme and it should function fine. With that set up the selector would also read safe and fire at the proper location just like it is in the lower you have now.

If you put your FCG in a steel HK lower you will have to change the selector to make it work. Then it would read fire when it was on safe and safe when it was on fire (unless you could get someone to modify a selector for a steel lower the way that 21Hk observed that your selector has been modified).

A third option is to put your FCG in an original steel Cetme lower (it would need to be clipped and pinned) and use the proper selector for that lower. It would then function correctly. However the safe and fire positions would be reversed which is the way that they were on original Cetmes. The steel Cetme lower looks almost the same as the steel HK lower but has different markings. It takes the same grips a steel HK lower.
Thank you both!

I've already got a grip (I bought a green furniture set from RTG), so I'm leaning toward option 3 (if I can find someone to clip & pin it).
If it ends up being too costly for what it is, I'll go with option 1.

But more importantly (functionally), I want to deal with the trigger and recoil first.
 

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You are very welcome and it sounds like you have your priorities in order.

If you do eventually go with #3, I posted the link for an unconverted steel Cetme lower it is only $19. I could not find a Cetme selector in stock anywhere but 21HK may know if an HK selector will work with your FCG. If not place a WTB ad on militaryfirearms.com. I am sure someone there would have one in fact someone over there might have an entire Steel lower off of one of the older Century Cetmes or a clipped and pinned one.
I am pretty sure Ghilliebear at PCS would clip and pin a lower for you for a very reasonable price.

Thank you both!

I've already got a grip (I bought a green furniture set from RTG), so I'm leaning toward option 3 (if I can find someone to clip & pin it).
If it ends up being too costly for what it is, I'll go with option 1.

But more importantly (functionally), I want to deal with the trigger and recoil first.
 

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I'm also a new C308 owner and just joined this site so I can learn as much as possible about HK91s and clones. I've wanted a G3 style rifle ever since I bought my SA M1A back in 2005. It was a choice between the PTR91 and the M1A and I decided to get the "American classic". But the 91 platform never left my radar. Fast-forward 12 years... I was in Cabelas two weeks ago and saw a new C308 on sale and couldn't resist. I ended-up scoping it with a Vortex Crossfire II with PEPR mount and finally shot it a few days ago. The wind was howling, but I still managed a 2.5" 5-shot group at 100 yards and am very happy with that result. The gun was also 100% reliable (which made me VERY happy, considering Century Arms' well-known reputation for unreliability in their older guns).

Right now I'm looking to replace the skinny forearm with a wide forearm ala the PTR 91. I think that I've found a source for a real HK wide forearm for $75. I'm making the ASSumption that it will fit my C308. Haven't ordered yet, but am getting close.
 
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