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Discussion Starter · #1 ·
I decided to go ahead and buy a new complete bolt assembly from APEX. I figured I'd need it eventually, and get it while the parts are still available. Anyway, I installed it in my CETME, and the bolt gap went from > .004 to .025. The new complete bolt assembly is around 1/32" longer than the original. My calipers don't stretch far enough to get the total length of the bolt assembly, so I had to use a tape measure.

So this leaves me with some questions.

1. What is the spec for the total length for a complete bolt assembly?

2. I put a complete unused bolt assembly in and am getting a gap of .025". I'm guessing that .025 is too high? Or will this work?

3. How do I measure the gap between the Rear of the Cocking Handle Support and the Carrier front tube? Anyone have a picture of where this is?

3. If the gap is too big, and the gap with the other bolt assembly is too small, what could be the problem?

4. I'm really leary of sending this rifle back to Century. If they send me a new one, will they send me junk or one that has proper bolt gap and is safe to shoot? I really don't like a crap shoot. The devil you know versus the one you don't.

Anyway, if anyone can answer these questions, I would appreciate it. I can't seem to find anyone with TOO big a gap, and I tried looking up bolt assembly length, and they show how to assemble the thing, no specs.

Thanks.

Jim
 

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If you do in fact have a Cetme Rifle, your New Cetme Bolt from Apex should be 1.835 plus or minus a thou.
A New Bolt will not increase the Bolt Gap. It should have lessened it.
If your old Bolt was ground on, that only increases the gap from a worn gun with an original length Bolt.

If you do have a cetme, you must have mixed parts with an HK. [probably the Locking piece]

Your old Bolt may also have been a HK which is shorter.

If you go to the "Build" thread in the Sticky you should find the actual HK and Cetme comparison.

gw11
 

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I am a bit confused! Didn't you mention in your thread a few days ago that you measured the Bolt?

Perhaps you are talking about measuring the complete Bolt and Carrier Assembly?

In that case, if your Carrier Tube is 1/32" longer and you now have too large of a Bolt Gap, your New Longer Carrier Tube is hitting the rear of the Cocking Handle Support from the poorly set Barrel and stopping the carrier from coming fully forward.

Please do Not Fire That Thing with the New Carrier!!!!!


gw11
 

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Discussion Starter · #6 · (Edited)
I am a bit confused! Didn't you mention in your thread a few days ago that you measured the Bolt?

Perhaps you are talking about measuring the complete Bolt and Carrier Assembly?

gw11
Yes, I meant complete bolt and carrier assembly. I won't be shooting it anytime soon.

Your New Carrier should be approx. 10 29/32" by ruler.
That's the exact length I have on the new carrier. The old one is 10 7/8" long. So that narrows the problem down to an improperly installed barrel, right?

Jim
 

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First off! Yes the Barrel is installed incorrectly. But I still feel that you have assembled something wrong!

Did you completely disassemble Clean and lightly lube the New Bolt/Carrier Assembly before installing it into your Gun?


If your old Bolt was the correct length and it had a .005" Gap with the old Carrier and +2 Rollers. Your Gap should not have changed with a New Carrier except for the New Locking Piece which may increase it some [but not .020]
That 1/32" difference in the Carrier length is also not enough to alter or Cock the Carrier in this case.

gw11
 

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jrswanson1

If your barrel and Cocking Tube were installed correctly, you would have a Bolt Gap of .016"-.020" and a Gap of .015"-.020" between the Rear of the Cocking Handle Support and the Front of the Carrier Tube.

If your old bolt measures the correct length and you need + size rollers to get it to within specs.- your Barrel is installed wrong!

If you have to remove or add Material to the Front of the Carrier Tube to get the Cocking handle to Function correctly , your cocking Tube was set at the wrong dimension from the Receiver. with relation to the positioning of the Barrel face.


Clean your New Carrier assembly and also clean the Trunion and Chamber and re-test the Gap.
You might also check to be sure your new assembly is not contacting something inside the Cocking Tube or Receiver. [perhaps someone altered the old Bolt/Carrier assembly] to get it to function smoothly.


gw11
 

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Discussion Starter · #9 ·
After I received the new complete carrier assembly (with bolt head, etc), I scrubbed it down with Simple Green and got all of the crap off. I lightly lubed it, and put it in my rifle. Pulled the cocking handle back, let fly, pulled trigger. BIG GAP, .025". The old carrier with a properly sized bolt head (I measured with caliper) and +2 rollers gave me a gap of .005". So, after all of this, the barrel and the cocking tube both are incorrectly installed. I will be sending the rifle back to Century with the specific problems. I will NOT be sending them my spiffy new complete carrier assembly, nor the other new parts. I will ask them to set the barrel in correctly, and to fix the cocking tube. You'd think they would check for these things before they send them out. I can see if they were selling them for $300 that they wouldn't put a lot of effort into them, but when they start going for $700 ($600 on sale!), I'd expect better quality.

Jim
 

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One more try here!

Remove your Stock assembly. With your New assembly installed, and the Cocking Handle locked forward and down on the Cocking Tube [it can't be slid to the rear] turn the gun upside down, slowly slide the Bolt assembly forward till it locks [snaps] in the Trunion, now check the Gap!

gw11
 

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I just can't help it, perhaps a need a few Beers!

Sorry to keep bothering you!

When you check your bolt Gap and you pull the Handle back and let it fly forward. Are you Locking the Handle in it's slot? Are you then slapping the handle from this locked position?

Or are you not locking it and letting it fly or helping it from the locked position and then letting it fly.

I realize this sound stupid but if you help the Handle in any way, it will fail to fall to it's popper position and catch on the forward pin or slide forward in a lifted [cammed] position. which will give a false stop on the carrier.


gw11
 

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Discussion Starter · #13 ·
With your new assembly installed. How is the Gun to Cock?
Is there any free play to lift the Handle?
Is the Handle hard to lift at all?
Can you feel any front to back play at the Cocking handle?

gw11

There is 3/8" of play in the cocking handle. It's a little easier to cock and pull than the original assembly. There is a little play front to back, but less than with the old one.

When you check your bolt Gap and you pull the Handle back and let it fly forward. Are you Locking the Handle in it's slot? Are you then slapping the handle from this locked position?

Or are you not locking it and letting it fly or helping it from the locked position and then letting it fly.
I pulled the handle all the way back and lock it. I slap the handle and let it fly. I am holding the rifle grip vertical and barrel horizontal. I pull the trigger with the rifle in the same position. I get a .025" gap. I'm even getting the same gap no matter which way I hold the rifle. I'm also getting this gap BEFORE I pull the trigger.

And gw, thanks for the questions. I really appreciate it. If I can get Century to fix my rifle the first time, instead of multiple trips, I'll be a lot happier. I just want a fully functioning, safe rifle. Thanks again.

Jim
 

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If you have a little play at the Handle, Your New Carrier assembly is not too long.

Can you hold your new Locking Piece along side your old piece, Are they exactly the same? [What Number is on it]
And is your new bolt 1.835" long?

One last thing and I'll go away!
With your New Bolt and Locking Piece removed from your Carrier, does your Carrier go forward all the way to the Trunion? [no space]

gw11
 

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I asked that last question and need to add. Does your New Carrier look exactly the same as your old one around the forward portion of the body? Any grinding of the corners or edges?

Can there be welds [inside] where to Trunion is welded to the Receiver inside the rails against the Trunion. This should be clean with no Welds. The Carrier should hit the Trunion.

gw11
 

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Discussion Starter · #16 ·
Can you hold your new Locking Piece along side your old piece, Are they exactly the same? [What Number is on it]
And is your new bolt 1.835" long?
They are the same, and the number is 50

One last thing and I'll go away!
With your New Bolt and Locking Piece removed from your Carrier, does your Carrier go forward all the way to the Trunion? [no space]
Yes.

I asked that last question and need to add. Does your New Carrier look exactly the same as your old one around the forward portion of the body? Any grinding of the corners or edges?
No, the nose appears to have a chamfer ground around the circumference.

Can there be welds [inside] where to Trunion is welded to the Receiver inside the rails against the Trunion. This should be clean with no Welds. The Carrier should hit the Trunion.
No weld marks in there.

An interesting note. I put the old bolt head onto the new carrier assembly and still got the .025" gap. But when I put the new bolt head on the old carrier assembly, I got a .015" gap. And that was with the old locking piece. The two bolt heads are exactly the same length.

Jim
 

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Now I'm almost exhausted on this.
Before you had a .005 Gap with your old Parts.
And now you have a .015" Gap with the old Bolt and LP in the new Carrier!

You also now said that the old carrier is a chamfer ground around the OD. Perhaps the Cocking Handle has been altered to allow for a Gap at the front of the carrier? Or there may be something in the Cocking Handle Support that should not be there. Or the Cam angle of the cocking Handle may have been altered to get the gun to cock easier!

There is something wrong and I wish I was there.



Again With the Stock assembly removed and the cocking handle locked forward and the Mag Well facing up. slide the New Bolt/Carrier Assembly slowly into the Trunion. When it Locks does it "Snap in" or is it sluggish? And what is the Gap.
Then do the same thing with the Old assembly!


gw11
 

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Discussion Starter · #18 ·
Now I'm almost exhausted on this.
Before you had a .005 Gap with your old Parts.
And now you have a .015" Gap with the old Bolt and LP in the new Carrier!
Old bolthead and new assembly = .025" gap
New bolthead and old assembly = .015" gap

Again With the Stock assembly removed and the cocking handle locked forward and the Mag Well facing up. slide the New Bolt/Carrier Assembly slowly into the Trunion. When it Locks does it "Snap in" or is it sluggish? And what is the Gap.
Then do the same thing with the Old assembly!
They both snap in.

Old assembly = .005" gap
New assembly = .029" gap

Jim
 

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OK
Since I expect that you have not given any bad info on your gun.

Since this still can not be solved with a build fault.
#1 I would not send it back to Century, You may have a close to correctly built gun [surprise-surprise]
#2 If it were me I would go the extra little bit and remove the Cocking Handle Pin and confirm that the Cocking Handle has not been altered.
I say this because you stated the Old Carrier Tube has a Chamfer around the End of the tube.
Perhaps as a last possibility this gun was built with the Barrel pressed too far Back giving the High Gap dimension with the New Assembly. If this is the case [GREAT]
Possibly the old Carrier and or the Old Bolt have been altered to get everything to lockup correctly within the High Gap Spec.
Removal of the Cocking Handle and it's Support may hold this answer. At lease you can compare the parts to known pics of these parts. [I think there are pics in the "Build" thread in the "Sticky".

With the High Gap Dimension the gun would be Harder to cock than with the Low dimension so some people have altered the Cocking Handle instead of shortening the Cocking handle Tube or the Cocking handle Support in an effort to get the Handle to Over Cam easier.

#3 If the Cocking Handle parts are OK, You may try one more thing, Install the Old Locking Piece [and save the new one for a rainy day] in the New Bolt/ Carrier assembly to see if the Gap Lowers to .020"

#4 Beyond that effort if you can physically qualify the Old Bolt "inside and out" as not being altered in a dangerous way, go ahead and use the Old bolt and New Carrier etc.

#5 As a last option order [Minus.008] rollers from [http://www.hkparts.net/shop/pc/viewCategories.asp?idCategory=113] They do cost $20.00 each but in this case they are worth it, unless they can be found elsewhere for less. These also come in "Minus.004" but in your case I would go with the -8's

gw11
 
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