What is This Clicking at Top of Bolt Lift?

[topwater225]

Hi guys-

A buddy and me just built 20BR's using the same reamer, and we are both having a weird thing happening when ejecting cases.

There is a clicking at the top of our bolt lift. You get a normal bolt lift to a point and then you have to exert extra force to 'click' open the bolt. It doesn't happen on every case, just alot of them.

I have used two different sets of dies and a small base die. The small base die was actually necessary to get the case to chamber, but it didn't help the clicking.

My guess is that its a headspace problem that should be solved by bumping the shoulder back more. However we are bumping it back as far as our die will allow. My buddy also tried to grind his shell holder down a hair to see if that would allow bumping the shoulder even more, but it didn't seem to help. Maybe he needed to grind it down even more....

Anyway, can anyone point us in the right direction? I'm sure someone on this forum knows what is really going on.

Thanks in advance!

 

[dantiff2]

I experienced the exact same problem with a 223 remington. The portion of case body just above the web area is not being sized by your die or your chamber is alittle smaller than your die so your cartridge is not being sized, try a new die or small base die and see if that helps at all...

Dan

 

[topwater225]

Thanks Dan....you reminded me of something to add to my post.

I have used two different sets of dies and a small base die. The small base die was actually necessary to get the case to chamber, but it didn't help the clicking.

 

[Bob3700]

Top,

I just went thru this with my 6MM XC bolt gun.

Had clicks at the top of the bolt lift. I tried a small base sizing die, the shoulders were being bumped back .002' and the click was still there.

Problem: You brass just above the extractor rim is too big for the chamber or the chamber is too small for the brass!

What are the origins of the chambering reamer? Did you order it? Did you buy it off the shelf?

If you ordered it, did you send a dummy round to the grinder for an example?

My reamer was ground for Remington and Tubb brass. I purchased some Norma brass and guess what, bolt clicks. Measured the head of the brass just above the extractor groove and what a surprise. The Rem and Tubb brass is .002' smaller in diameter. Switched to Rem brass and no bolt clicks.

It would seem that you can only size the head of the brass case down so far and that is it.

Solution: Tried new brass? If new doesn't work, I would have the reamer reground for the brass you are using if possible and re-cut the chambers.

It is either a very easy fix or a hard one.

Give the new brass a try. You shouldn't have to size new brass to get it into your chamber. If so, the chamber is cut too small.

My .02

Bob

 

[1shot]

I had the same bolt click issue, but my problem was a miss-formed sizing die. In my 6.5x284 new brass would chamber and eject just fine. However after the first re-sizing I would get the click and a very hard bolt lift at the end. So hard in fact that I broke two Sako style extractors before we got the problem figured out. When the sizing die was cut, there was a burr on the tool that left a groove at the shoulder/body junction. When I re-sized the brass, a ring would appear, and catch in the chamber, causing the hard bolt life and extraction. The company quickly replaced the die and I should receive it today. I hope this helps,
Lloyd

 

[BoydAllen]

Shoulder bump has nothing to do with click. The head of the case is interfering with the very back of the chamber. Chances are, your chamber is too small right at the back. When a chamber is too small, relative to the brass, the pressure of firing will expand the solid head to a slightly larger diameter that drags that thick case wall just in front of it out with it. You can do all sorts of stuff to try and deal with it, but making the chamber two thousandths bigger in this area by polishing it out on the lathe will solve your problem. The size of your reamer in this area is the root of the problem. Small base dies are not a good fix because the problem is just beyond the reach of a standard type die. 6PPC shooters have been all through this, and extensive postings have been done on www.benchrest.com If you had to use a small base die to chamber new brass, your chamber is really out of whack in this area, as the problem usually surfaces after a few high pressure firings. If it happens after firing you might want to look at how loose your primer pockets are and/or how much your case heads are expanding.. You may be running more pressure than you realize.

 

[topwater225]

Thanks for the help, guys!

The reamer we used is an older one. My guess is that it's probably based on the 6BR Remington case and not the 6BR Lapua.

I wonder if the best thing for us to do right now is split the cost of a new updated 20BR Lapua reamer a re-cut the chamber.

I don't want to try new brass as I am sure that it will start clicking on those as well. Plus there is quite a bit of work to just to get a new piece of brass 20BR ready.....

 

[MarkS]

topwater225,

I can see this in my 6BRX. The butt of the case is tight, as said below. The shoulder would be in the closing of the bolt on at the end. If you have a Rem Chamber that may not be helping.

I had a Rem 40X in 6BR. The small base die would let me shoot Laupa brass with no problem. Your's must be tighter.

I resized my BRX with a 308 F/L for the base and a 6BR body for the shoulder. You may try another die that would not touch the shoulder like 308, 7mm -08, with the cut shellholder, before recutting the chamber.

If that does not work, rechamber may be the way to go.

Mark Schronce

 

[topwater225]

Yeah, I am going to speak with the gunsmith tomorrow and decide which option is the best. I think polishing the chamber out would work for the click, but now I wonder if the best thing to do is re-cut the chamber with a newer updated reamer. Just like Boyd Allen said, if a small base die was needed just to chamber a new piece of brass then the chamber must really be out of whack. Well....that's my feeling too. :,

 

[Preacher]

I always figured that the click was associated with a out of time bolt.....

 

[GerryM]

I agree with a few of the post on the click. Usually it is caused by the base needing sizing and a bump of the cases.
Try full length sizing with a small base die. If the problem doesn't go away then IT may be bolt timing.
Usually bolt's going out of time are caused by lapping the lugs too much or a bolt handle that is in the wrong position.
I hope the sizing works out for you.

 

[topwater225]

If it was a bolt timing thing, wouldn't it happen on every case?

I would say the mojority of the cases do not click, but close to half do....they are all new cases shot one time.

I have used 3 different dies....a body die, a full length die, and a small base die.

Does anyone know how a gunsmith would polish the chamber? Just asking as I am wondering if this is somehting I could do.

 

[RJinTexas]

I'm assuming that being this is a 20 cal it's going to be used as a varmint rig and if it's going to see a lot of high volume shooting your going to have more trouble then it's worth if you don't get a little more clearance. I've found out over the years that tight chambers are a pain in the ass in the dog towns.

Good luck
RJ

 

[topwater225]

Well....hopefully the saga has ended. We spoke to a well known gunsmith who told us exactly what has already been mentioned and then some. He also told us what to do to fix it.

First he told us that the older reamers were notoriously known for tight chambers, and that is exactly what the problem was. He then told us how to polish the chamber with some emery cloth, which we did. We took just enough out that our most tight rounds would chamber and eject without a click. So, I am feeling pretty good right now, but stay tuned as only testing will tell......

And oh, by the way....you are correct RJinTexas, as this was built for predator calling and I agree that I don't want to be messing around with an overly tight chamber.