Sticking Cases in Quadlock

[257Roberts]

I've been shooting, competing and reloading for over 25 years. I can't even remember the last time I bought factory rifle ammunition. I like to think I know what I am doing, but I am always playing with something new and learning at the same time. Right now I am struggling with two rifles, an RPA Quadlock and an M1A NM. I already posted the M1A thread for those interested.

This RPA Quadlock is a real shooter! 6.5x284, shooting 150gr SMK into 0.25-0.3MOA at 100yds if I do my part. Struggling with ES/SD and have been hoping to do some node testing to get it in shape for 1000yards. Anyways, had a few rounds, now once fired Lapua brass, chambering really hard. Finally stuck one in the pipe on Wednesday. Wasn't stuck too terrible, it easily tapped out with a cleaning rod, but there was no way I was closing the bolt.

I was pretty anal working this brass this time around, looking for that magic .001-.002 shoulder bump. And I got it at about 1.802". Checking new Lapua brass, its about 1.797-.798". All well and good I think. Base diameters the same, case length still .007" short of max. I am using a .293 bushing and my sized cases measure just that.

Here is where I think the problem is. On a loaded round, I get 0.294" throughout the body of the neck. I like that, approx .001" neck tension. But if I measure neck OD at the very top of the mouth, I am getting .297-.298". I believe this larger "belled" area is what's keeping me from closing the last bit of the bolt stroke. Looking at a loaded case, I can even see the "belling" at the mouth. Kind of reminds me of loading pistol cases, but obviously not that severe of a bell.

Would folks agree this is the likely culprit? When chambering an empty piece of sized brass at .293, they chamber just fine every time. So my question is, what the heck am I doing to cause this "mushroom" at the mouth of the case? I am really kind of stumped on this one. In this case, I did NOT trim the cases after the first firing. So they arent deburred and chamfered either this time around. I have never had this problem before, or at least have never had a gun with this tight of a chamber to notice my reloading error.

I guess my first thought was too remove the belling, and try again.
If still a problem, then I would go for more shoulder bump, but I really don't believe that's the issue.

Thanks for your advice as always!

 

[piie]

My first thought on the belling would be incorrect crimping. Either that, or double-check your seating die setup to make sure nothing is trying to force the case "down" ( is the seating die bottoming out on the case mouth?) - brass will only have one place to go if that is the case and that would be outward.

 

[gme]

if the neck protrudes out the top of the bushing it will "bell" at the mouth

 

[257Roberts]

if the neck protrudes out the top of the bushing it will "bell" at the mouth

How do I check that with the die assembled? Nothing on the case is measuring too long.

And it shouldnt been anywhere close a crimp, as the die is screwed out at least a turn and a half to see the depth graduation marks.

 

[gdbleb]

Is the "belling" happening from the sizing die or the seating die or "what's behind door #3" ? Sounds like the seater from your description. Run a good test case (brass only) up each and measure to find the culprit. Sounds like you're hitting the top of one or the other. What does your seating stem look like?

 

[RegionRat]

Like Gary points out, check to see if the cases come out of the sizing process already bell mouthed.

A type S bushing die allows you to back the bushing off independently of the shoulder bump. It should be simple enough to detect the belling is present or not right after sizing. Then we can help you understand how to adjust the bushing.

 

[SBS]

On determining whether the neck protrudes out the top of the bushing, you can take the bushing out and visually compare it to the portion of the sized neck and see if it would have gone out the top. You apparently have pretty tight fit in the neck area and the bulge at the top will cause difficulty in chambering a round. A fellow shooter had the same problem, took him awhile to measure the top of the neck and figure out it was the culprit. Wound up having to turn the neck to get the end of it down to size. Maybe chamfering it before resizing would have helped. You can always run it through a standard non bushing fl die (if you have one) and see if that flattens it out. Another thought, if the bullet is hard to get started, perhaps the seater stem is not concentric and the bullet starting in the neck crooked is causing the bulge. Some shooters have reported seater stem damage that causes problems. Also having the seater die body screwed too far down can cause your problem on some seaters that have a crimping provision.

 

[Uncle Ed]

I do not understand how if the case neck extends past the top of bushing causes a belled case mouth.

You still have to pull the case neck back down through the bushing on the downstroke of the ram.

 

[257Roberts]

So I am finally back to troubleshooting my reloads for my 6.5x284 Quadlock.
Recap: First firings of FL bushing sized NEW Lapua brass worked fine. No issues.
I am using a 0.293 bushing. I was getting honest 0.25MOA groups first pass thru 100 pieces of brass.

Now on this once fired brass, fully cleaned. Case length is still fine at 2.164-2.165.
After FL bushing sizing, the OD of my necks is 0.293-0.2935. I checked several spots along the neck and several cases. All show conformity. So no belling is happening during the sizing process that I can tell.

However, when seating the bullet [150gr SMK measuring exactly .264 on several bullets], the very brim of the case neck is belling to about .296-.298 and the rounds simply will not chamber.
Below the mouth/brim I can measure .294 all the way up the neck, and the pincher jaws will literally "catch" under the brim.

I checked some case neck thicknesses and get anywhere from .0156-.0160. Using a .0158 average that equates to a .296 OD worst case, i am not sure how I can get .297-.298 pretty regularly on a seated bullet.

I tried trimming back to 2.160" to see if I could [knock off] the trouble area before seating a bullet. And it works on a couple, but not all. I still get .296-.297. I got one at .295 and it will chamber fine.

Apparently this thing has a tight neck, even though I requested to be able to "no turn" Lapua brass.

Any thoughts on what the issue might be?

I am trying to understand what would cause the very brim of the case neck to "bell" wider than the rest of the neck when seating a boattail bullet. Baffled at the moment.

Now, I do have the sizing button removed from the FL bushing die. I do this with all my bushing dies and have never had a problem. I am using Lapua brass with bushing dies, and so far I have gotten away with it. I am trying to understand how pulling a sizer button back through the neck would help the OD of a sized case? In my mind, it would potentially make it works, pushing out any imperfections.

I think I am looking at neck turning for this gun. I have the stuff to do it, though I was hoping to avoid it.
I think I need to get to .015" thickness to ensure a .294 neck OD.

Am I on the right path?

 

[BoydAllen]

When specifying a chamber neck, you should be specific. Give a dimension. For a no turn in that caliber I would want .0035 clearance over the largest diameter of loaded necks. Some years back in a discussion about what chamber to order a friend kept going on about SAAMI minimum but had no idea what dimensions that entailed. I find this sort of thing all too common. If I have fired brass to work with, I like to buy the FL die first, size cases and then order a reamer for the clearance that I want. I prefer that the cases be well used.

 

[257Roberts]

I confirmed with the gunsmith that the chamber is .297" so my .294" loaded cartridges should be about perfect, and they have been functioning perfect until this loading.

Literally just the "brim" is opening up to .297-.298 which is causing the problem. I've got a couple recommendations to try today and I will report back with results.

 

[mikecr]

Just seems like a chamfering deficiency.
What did you do there during preps?

 

[257Roberts]

I talked with a pro and he gave me some good advise. When I described my issues, the first question he asked was "do you high speed tumble with pins?" The answer is yes, for about a year now. So far, never had an issue. Upon further investigation, it appears this is a well know problem, where either too few pins, too much brass, not enough water, too much time or a combination of all of that, will cause the brass to crash into each other enough to "peen" the case mouths. Upon close up inspection of my brass, it sure does. I was also told that this peening induces stress to the case mouth, which can cause the belling or peeling when seating a bullet. I believe it now.

My loading method for this once fired Lapua brass was, de-prime, clean primer pocket, SS wet tumble, measure length [good at 2.164" for a 6.5x284], FL size with a .293 bushing, Seat a 150gr SMK with a Redding competition seater. Its literally the last .025-.050" of the neck that shows damage and starts to flare open upon seating a bullet. The maximum dimension .297-.298 doesn't fit in my barrel with a .297 chamber. The rest of the neck, from the shoulder all the way up to this last expanded brim is a perfect .294-.295 that I am looking for with no neck turn Lapua brass.

I first tried just a heavy chamfer/deburr with my RCBS tool and it didn't make much difference. It might have knocked the OD down .001 at most. But still wouldn't chamber in my rifle.

I then tried an anneal, only and it didn't make a positive difference either. Maybe actually made the issue a .001" worse.

I then did a minimum length trim back to 2.160" [ I believe this is what new Lapua starts at], and another heavy deburr/chamfer. I then loaded a bullet and the belling is gone. .294-.295 at the mouth of the case, which is pretty good for my .297 chamber.

So the real test will be after this firing, without any cleaning or a different cleaning method, to see if the mouth will bell out with seating a bullet again. I suspect likely not.

Maybe my RCBS chamfer tool isnt very good and I should try something else.