Puzzled (rounds not chambering)

[K22]

I sorted all the bullets from a 500 box by BBTO. (All these rounds were loaded from the same BBTO lot.) I seat by measuring CBTO. I measured touch using the Wheeler method as 2.200". All using the same comparator. I've shot a lot of the 300 rounds so far (excl today) at or very near touch. With these rounds even 30 thou deeper doesn't resolve the issue.

So, even seating .030" from the lands you still experience chambering difficulty. Well, I guess that rules out bullet seating which surprises me because if I read your posts correctly, the only time you experience problems is with a bullet in the case. Is that right? Is so that kind of rules out sizing.

That leave an issue with the rifle chamber or something with the bullet. You said you checked the chamber and all looks fine. Maybe try another bullet and see what happens.

 

[JLT]

So, even seating .030" from the lands you still experience chambering difficulty. Well, I guess that rules out bullet seating which surprises me because if I read your posts correctly, the only time you experience problems is with a bullet in the case. Is that right? Is so that kind of rules out sizing.

That leave an issue with the rifle chamber or something with the bullet. You said you checked the chamber and all looks fine. Maybe try another bullet and see what happens.

I'm with K22 on this. The marks on the bullets in the pictures are not what you would see from contact with the lands. There's an obstruction issue or an alignment issue. The leade (freebore) is typically .0005" larger that nominal bullet diameter - it doesn't take much to gum things up. The chamber may not be coaxial with the bolt face, the reamer used to chamber the barrel could have been a bit out of spec, etc.

 

[SGK]

I would chamfer, inside and outside one of the cases, re-seat a bullet and try again.

Hi. I tried this with the round I pulled the bullet from. It seems to help! While the photos are heavily zoomed in I accept I could do a much better/more aggressive job de-burring. Maybe...the case sits up just enough on the burr that with a bullet seated there's interference with the bullet but without the bullet the cases chamber fine in the wider relative space of the chamber neck area? (Interference at bullet, but problem with case - not shoulder but the burr on case mouth.)

See pic of pulled bullet and better de-burred case.

If there was a problem with the chamber the scuffs on the bullet would appear all around it as I repeatedly tried chambering the round (each time the round might be sitting differently on its rotational axis in the chamber). If some one point on the case mouth is causing the bullet interference that interference would be the same spot each time...? (which it is)


And here is a close up photo of the dummy round I had used to find 'touch' with the Wheeler method (and kept in my case box as a reference since). I had been loading to this CBTO. It chambers easily. And doesn't have the 'bad' case mouth.

 

[SGK]

I need to pull bullets from some of the other problematic cases and repeat this test.

 

[Whisky Tahoe Foxtrot]

Well at least you are having fun . Thanks for keeping the group informed.

 

[SGK]

Oh yeah this is a lot of fun I hate deburring/chamfering and it's perhaps not surprising it has been my downfall. It's been a frustrating 24 hours.

I've done the test suggested by Frank 7 times now and each time doing a better job of deburring/chamfering the case mouth has remedied the issue. So thanks, Frank, for suggesting I run that test.

Perhaps it was also exacerbated by the build up of carbon in the freebore area. I've ordered some JB Bore Compound and the soaking in Bore Tech C4 seemed to clear a lot from what I can see in my borescope. I will give it all another clean when the JB arrives.

Thanks to everyone who offered their views. I very much appreciate it! Hopefully next trip to the range I can focus more on my shooting and have more rounds to practice doing better on an MR-63FC at 300 yards... (Attached my 20 round 'self test' from yesterday with sighters patched. The 9 came out of nowhere as I'm sure they always do. At some point I came up 1/4 MOA on my scope elevation. I need a LOT of practice.)

 

[bozo699]

Oh yeah this is a lot of fun I hate deburring/chamfering and it's perhaps not surprising it has been my downfall. It's been a frustrating 24 hours.

I've done the test suggested by Frank 7 times now and each time doing a better job of deburring/chamfering the case mouth has remedied the issue. So thanks, Frank, for suggesting I run that test.

Perhaps it was also exacerbated by the build up of carbon in the freebore area. I've ordered some JB Bore Compound and the soaking in Bore Tech C4 seemed to clear a lot from what I can see in my borescope. I will give it all another clean when the JB arrives.

Thanks to everyone who offered their views. I very much appreciate it! Hopefully next trip to the range I can focus more on my shooting and have more rounds to practice doing better on an MR-63FC at 300 yards... (Attached my 20 round 'self test' from yesterday with sighters patched. The 9 came out of nowhere as I'm sure they always do. At some point I came up 1/4 MOA on my scope elevation. I need a LOT of practice.)

View attachment 1344196

We all have had these big problems that usually turns out as a pretty simple problem we have just over looked!… at least with a simple problem easily fixed by trimming or de burring shoulder bump etc… it’s just time and frustration unlike a real problem like a bad chambering or other problems needing a Smith or new parts to resolve !.. at any rate we have had 4 pages of head scratching and fun helping you figure it out without a bunch of mud throwing!.. I enjoyed your thread and hope your problems are resolved good luck to ya sir!..
Wayne

 

[MUP]

Have you tried a different rifle? I jest. Glad you got it figured out!

 

[Stumpy1]

Oh yeah this is a lot of fun I hate deburring/chamfering and it's perhaps not surprising it has been my downfall. It's been a frustrating 24 hours.

I've done the test suggested by Frank 7 times now and each time doing a better job of deburring/chamfering the case mouth has remedied the issue. So thanks, Frank, for suggesting I run that test.

Glad it worked out for you! This isn't the first time I have seen this issue, and it probably won't be the last, but maybe this thread will help other folks out.

Most often happens with pin tumbling, but can happen in other ways too.

Frank

 

[243winxb]

All the ones that chambered have been shot. But loaded rounds have a neck of 0.269" as noted above. Fired brass has a neck diameter of 0.2715" (versus chamber reamer dimension of 0.272")

Has brass been outside neck turned for the tignt chamber? And if NT, was it into the shoulder?
If problems is solved, i missed it.

 

[243winxb]

deburring/chamfering the case mouth has remedied the issue.

As would neck turning. IMO. Your photos dont show any brass that have been neck turned?

My brass for a factory chamber.

 

[243winxb]

If line is from neck turning, that neck is comming off , soon or later. Hope i am wrong.

 

[SGK]

Hmm very good question. The brass was neck turned originally but it's not from that. That particular photo is of the dummy case I used to recheck 'touch' and have kept as a reference, so maybe it was 1x fired. But the mark is on all my brass even the now 4x fired from earlier this week. The bushing stops a little higher up. From my die when bumping shoulders? I'm wondering whether to put the brass through the lathe again and then see how its looks.

 

[SGK]

I put one case through my 21st Century neck turning lathe that hasn't been used (albeit transported in a house move twice) since I turned this brass originally. I need to adjust the lathe slightly as I was aiming for 13 thou neck thickness and post turning have closer to 12.8 thou. Nonetheless a good deal of brass was removed suggesting the need to turn all the brass again. Here is a pic, as best as I can take with my iPhone, of the newly turned brass neck.

 

[bozo699]

I put one case through my 21st Century neck turning lathe that hasn't been used (albeit transported in a house move twice) since I turned this brass originally. I need to adjust the lathe slightly as I was aiming for 13 thou neck thickness and post turning have closer to 12.8 thou. Nonetheless a good deal of brass was removed suggesting the need to turn all the brass again. Here is a pic, as best as I can take with my iPhone, of the newly turned brass neck.

View attachment 1344422

That looks perfect just a skim turn into the shoulder just a touch
Wayne

 

[243winxb]

I full length size brass,after firing, in standard die. Die set in full contact with the shell holder, using expander. Outside turning is with a Lyman attachment on the old trimmer. The attachment has been discontinued. May not be a good method by todays standards?

I have noticed, making a 2nd pass, after the first, does remove more brass. May be a clue its not a great tool?

Next loading is with a Redding type S fl bushing die. Then i check the loaded rounds neck OD with a micrometer. Seems ok for my larger factory chamber.

A tight neck chamber has to be better.

Not saying my method is best.

 

[SGK]

I have noticed, making a 2nd pass, after the first, does remove more brass. May be a clue its not a great tool?

With the 21st Century tool, if I don't go too quickly, I find I can put a case through twice in succession without removing more brass on the second go. What's less repeatably is my ability to measure brass thickness a couple of years apart and yield the same answer...

I've had enough for today after turning 98 pieces of brass which required me to resize the fired brass and unfired from which I pulled the bullets, put it all through an expander mandrel and then turn it. I still need to resize the unfired brass again to reduce the necks back down. I will try to keep an eye out for when that ring forms again.

I've learnt a lot in the last 48 hours. Thanks all!

 

[SGK]

Loaded 65 rounds (all remaining 3x fired brass) after doing the work mentioned above. All chamber easily. Phew! Thanks again guys. I would have been completely lost without you.

 

[bozo699]

Loaded 65 rounds (all remaining 3x fired brass) after doing the work mentioned above. All chamber easily. Phew! Thanks again guys. I would have been completely lost without you.

Thanks for coming back and letting us know!… most everyone on here definitely including me has need help from this forum and in most cases the problem does get solved!…. In most cases it is dependent on the op to tell the truth, stay calm and not get mad at the silly answers or the ones who skim and don’t read everything and you end up repeating yourself over snd over again . Which you did all of those things so it was easy and a pleasure for all of us to help you!.. what exactly was your final outcome or rather what one thing fixed the problem or was there multiple problems in the end?.
Happy shooting and looking forward to your next thread
Wayne

 

[Bc'z]

At 20 thou deeper I'm getting an easier bolt close. Also, you can now see better the scuffing on the bullet, always in the same area butt spreading further back as I seat deeper. It puzzles me that as I have randomly placed the cartridge in the action why the scuffing isn't forming all around the bullet...

View attachment 1344052

Carbon ring