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Post by snooker on Jan 23, 2020 15:04:16 GMT -8
Assembled my 243 LBC and found that the bolt won't close on a chambered round. The end of the bolt carrier stops a full 1/4 inch from flush with the upper receiver. It will lock up without issue on an empty chamber.
Brass is new 6.5 Grendel, sized and necked down using Redding #77478 full length die and .269 neck bushing. The same brass that won't allow the bolt to close in the 243 will chamber and lock up just fine in my 6.5 Grendel. Measurements of a chamber cast seem to allow for sufficient clearance when compared to the brass dimensions. The barrel and bolt were purchased together and reportedly headspaced before shipping.
I am stumped. Anyone have any guidance
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Post by GLSHOOTER on Jan 23, 2020 15:19:27 GMT -8
This might sound dumb but when you drop a round in the chamber and look in there does it appear the cartridge is seated deep enough? I'm guessing you are doing this with just a sized case without a bullet?
Stick a 135 Grendel bolt in that BCG and see what happens.
Greg
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Post by snooker on Jan 23, 2020 21:30:41 GMT -8
No bullet. The case head is approximately .020 further out of the chamber than where my Grendel sits. Can't try swapping bolts. The 243LBC has radiused lugs and my others are square. Seems odd that the bolt carrier stops so far out of the receiver. I don't have a "go" gage, just using a sized case.
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Post by snooker on Jan 24, 2020 6:05:24 GMT -8
Resized the brass with no floating the neck bushing after centering. Was then able to close the bolt with a forceful push from behind on the bolt carrier. That's a positive. Extraction was difficult. 269 bushing is yielding minimal grip on the bullet so I am going to step down to 267 and take it from there.
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Post by GLSHOOTER on Jan 24, 2020 9:59:34 GMT -8
You could bump the shoulders a tad but the design is set up to merely neck size fresh brass. If it were me I'd be contacting BHW and letting them correct the chamber as based on what you are saying it is tiny bit undersized on the shoulder height.
I am curious on the radiused vs "square" lugs. I'm unfamilair with that. If it goes in one extension any should go in the others. BHW uses a standard extension, at least on the three dozen I own, so I don't quite get it. Could you enlighten me?
Greg
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Post by snooker on Jan 24, 2020 16:25:57 GMT -8
Not a BHW product. Called a Titan bolt, from AR15 precision.
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Post by GLSHOOTER on Jan 24, 2020 18:13:47 GMT -8
Not a BHW product. Called a Titan bolt, from AR15 precision. In that case it's time to contact them directly. That is all their design so they will have to handle it. Tolerances could be totally different when using the non-standard bolt. Greg |
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Post by ltdan on Jan 24, 2020 19:05:20 GMT -8
A Titan bolt only fits a Titan extension from what I'm told
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Post by GLSHOOTER on Jan 24, 2020 19:14:28 GMT -8
A Titan bolt only fits a Titan extension from what I'm told That is also my understanding. I'd quit spinning my wheels and give them a call. Greg |
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