[Eric556]

Regarding my CAI M1, I can relate an interesting phenomenon. After I purchased it at a gunshow in 2000, in Savannah, GA (I was stationed at Ft. Stewart with the US Army at the time), I decided to replace the stock with a Boyts because of a 6 inch long split in front of the trigger housing and the significant air gap between the stock and the rear of the receiver, which all the CAI's seem to have. However, with the new stock, the rifle malfunctioned! After firing the first round of a clip, the hammer would not engage the sear when the rifle cycled, but would follow the bolt forward, the firing pin leaving a small dent in the primer. The same thing happened when I tried the US GI stock from my DCM Springfield M1. No slam or out of battery fire, fortunately, but I imagine an 8-round full auto burst (or worse) could have been possible! I tried several GI as well as new production stocks, and tried different trigger groups, but the rifle would only function with its original trigger group and original stock (with the air gap and split)!
After some reading (Kuhnhausen, Duff, et al) and visually scrutinizing many manual cyclings of the action, with and without the stock, with and without holding the trigger during cycling, and with and without me applying various amounts of torque to the trigger group, I determined that a unique combination of CAI receiver, original trigger group, and mil-spec stock, resulted in just enough downward displacement of the trigger group to prevent engagement of the hammer hooks with the sear, preventing cocking after the initial shot.
So I replaced the original stamped trigger guard trigger group with a milled GI one from Fulton Armory, and the rifle now seems to function as it should with the new stock.
I believe the problem is corrected since the rifle functions without a hitch now, but it seems to confirm for me what others have said about CAI receivers--that the geometry is just a little "off." A receiver that requires such a unique combination of components to work right sort of makes a mockery of Eli Whitney's 19th century concept of weapons made with "interchangeable parts"!

Anybody else have any similar experiences?

Eric556

 

[Oldnugly]

Eric. Have you tried the stamped guard assembly in your DCM
that came with the milled guard?

 

[wes]

Have not heard of that. I put a Boyds stock on mine and it functions fine. I did have to do some minor fitting inside the stock,the op-rod was dragging slightly. Could it be that the stamped trigger assm. was too loose with the new stock?

 

[Robert C]

more than likely this is what happens...on the rear slot where the rear of the trigger housing sits, there is a smaller cut in that slot.. that might be interfering with the triger... this happend to my dane stock i fitted to my JCG Garand i set up......

 

[Stock Doc]

The dimpled primers is a normal thing with the floating pin. It taps on all rounds as you drop op rod in place with rounds. Dont worry it wont fire a round. I was scared the first time I saw this also. Rick B

 

[Eric556]

Thanks for the quick feedback, guys. I'll respond in order:

Oldnugly, I sure did. I also have a "Tanker" (cutdown Springfield), as well as a full-sized Springfield DCM, and I switched components all around. The Springfields would work with any stock or trigger group combination, but the CAI was very picky!

Wes, maybe, but it didn't rattle like anything was obviously lose--in fact, my working hypothesis was that any stock except the original was so tight, it was pulling the trigger group away from the receiver just enough to prevent engagement of hammer with the sear during cycling.

Robert C, yes, I thought that might be the trouble, and tried filing, sanding and whittling a number of areas on the stock, including the location you mentioned, but no soap. Everytime I thought I'd trimmed the stock just right, and solved the problem, I'd discover that I had not. I only managed to trash two stocks, one new, one old (a carpenter I'm not!).

Stock Doc, that's good to hear. The real problem was not so much that I was dimpling the primers, but that the rifle wouldn't cock after each shot. The hammer hooks wouldn't catch the sear and the hammer would be in the forward position after firing a round. They would, however, catch and cock when I manually pulled the bolt back (ejecting a live round). So my 8-shot gas operated semi-automatic had become a 4-shot manually operated straight-pull bolt action (with 4 empty cases & 4 live rounds laying on the ground next to me!)

Hey, this is a great forum! I wished I'd had access to your experience and expertise when I first started struggling with this problem. Everyone's response is greatly appreciated.

 

[wes]

Eric,glad to have you here,we can ALL learn from each other.

 

[Big John]

This is a fairly common problem when bedding a rifle or changing to a new, after market stock. The trigger group is misalligned with the barrel/receiver group due to interference by the stock. Here's what you do:

Step 1: Perform a "Sear Capture Test" to confirm the suspected problem.

The sear capture test is fairly simple. With the firearm unloaded, charge and close the bolt. Pullthe trigger, dropping the hammer and hold the trigger agaqinst the over-travel stop. With the trigger remaining in that position, open the bolt to full retraction and then release it. With the bolt now closed, release the trigger and then pull it. If the hammer fails to drop, then the sear failed to capture the hammer. Repeat the test a few times to confirm that whatever happened the first time wasn't a fluke.

Step 2. Repair

The usual cause of a sear capture failure is a mis-allignment of the trigger group in the stock, usually the trigger group is cocked/canted to the rear. Careful removal of material from the stock contact area to the rear of the trigger group will re-allign the trigger group sufficiently for the sear to completely capture the hammer, eliminating the problem for good.

John

 

[wes]

Thanks Big John,great info.