I have a falling block, single shot rifle with a tight-necked chamber.

I also have a few hundred rounds of good, expensive factory ammunition for this rifle.

The ammunition comes from several lots.

Some of it will chamber easily (and shoot excellent groups) and some of it will chamber a bit on the hard-to-chamber side (and also shoot excellent groups).

But some of it will not chamber at all.

Fired case necks measure the same diameter as the necks of the impossible-to-chamber loaded rounds.

What I would like to do, if it is possible, is to turn down the neck diameter of the loaded ammunition that will not chamber.

What I don't want to be forced into doing, is to disassemble all of the great shooting ammunition that won't chamber, just to outside neck turn the cases the couple of thousandths needed to make sure that they will chamber, then reassemble the ammunition.

I would greatly appreciate any advice as to how I can achieve my goal, and avoid all the work of disassembly/reassembly.

Thanks.

How do you know it is the neck and not the shoulder? How have you measured these?

quote:

Fired case necks measure the same diameter as the necks of the impossible-to-chamber loaded rounds.

I'm not sure that indicates a problem with the neck. You might want to take a chamber cast. It's possible that the brass is allowed to expand another .002" or .003" and then contracting back when it cools. Until you measure it, it's possible that your neck isn't too tight at all.

If it truly is a tight neck, even though it might be possible to turn the neck, I'd avoid trying to turn the neck of a loaded cartridge.

You could also consider having your neck reamed a little if it really is too tight.

How about checking OAL, or at least whether the round is failing to chamber because of the ogive? I do not know how to turn case necks of loaded rounds as normally the case neck has to be supported. I would smoke or mark the case and bullet in some way and then chamber it to see where it is "hanging up".
Peter.

It is relatively easy to turn the necks of loaded ammo provided that you have a relatively long bullet extending out of the case.

I have tight neck problems with all the Norma, cases in 22PPC. I must turn them all down. First of all pull the bullet on one and turn the neck down no more than .002". Than try chambering the case. If it chambers you have probably correctly identified the problem.If it doesn't chamber full length resize it and try again.
If it is the neck you might try a little neck reaming or lapping.Just a thought. roger

quote:

Originally posted by SR4759:
It is relatively easy to turn the necks of loaded ammo provided that you have a relatively long bullet extending out of the case.

Okay, I'll bite.

I have a long enough bullet.

quote:

Originally posted by bartsche:
I have tight neck problems with all the Norma, cases in 22PPC. I must turn them all down. First of all pull the bullet on one and turn the neck down no more than .002". Than try chambering the case. If it chambers you have probably correctly identified the problem.If it doesn't chamber full length resize it and try again.
If it is the neck you might try a little neck reaming or lapping.Just a thought. roger

These are Norma, too.

Another brand (Hirtenberger) is 0.004" smaller in neck diameter, on average, and they chamber just fine.

I think a reduction in neck diameter of 0.002" will do the trick for these.

Just don't know how to get it done without pulling the bullets, etc., etc.

If you can't easliy finger insert a bullet fully into a fired case neck, I wouldn't shoot anymore of that ammo until you get the problem resolved. With insufficient release clearance, it is possible to generate some outrageous pressures.

Iwould take a sharpie and color the case of the
rounds that won't chamber. Then try to chamber them and look for the place where ink is rubbed off. Also get a ball mike and check the neck thickness of your rounds. Check COL and compair your headspace on the fired and non chambering rounds. You will find your problem if you do these simple things.Keep your Eyes open. Good luck.

What NFMike said: If you can't insert a bullet into the neck of the hard to chamber case after you have fired it, you have a tight neck.
On the hard to chamber cases, after they have been fired, what does the head look like? Flattened primers? Ejector marks? Head stamp smeared?

quote:

Originally posted by mrlexma:
I think a reduction in neck diameter of 0.002" will do the trick for these.

Just don't know how to get it done without pulling the bullets, [i]etc., etc.

If I had to do this to my ammo, I'd do it like this: Chuck the case head in this lathe. Mount a Stoney Point OAL insert appropriate for the bullet diameter in a tailstock drill chuck. Turn off .002", being very careful not to go too far into the case neck/shoulder junction.

My first thought was to use a Forster case trimmer with the outside neck turning attachment but it requires a mandrel be inserted into the inside neck to center it. Having a bullet there negates that proposition.

quote:

My first thought was to use a Forster case trimmer with the outside neck turning attachment but it requires a mandrel be inserted into the inside neck to center it. Having a bullet there negates that proposition.

Same on a Lyman. Take a bullet seating stem from a seating die and turn it to fit where the pilot goes, might work.It may need to be spring loaded like a plunger so it can move in and out.This will mark the bullet, how much, dont know??? It will not be very accurate, to much play in the cutting shaft i would guess. Best to pull the bullets and start from there. Turning makes HEAT, be carefull.

No pressure signs and no problem inserting a bullet into the fired case necks.

This is a tight-necked chamber. Very accurate, but very picky to feed.

I was afraid that there was no easy way to fix these thick-necked rounds.

Tight-neck chambers and factory ammunition do not go together.

If the bullets inserts easily, then you DO NOT have a tight neck situation. I'm gonna guess that some other small diminsion is at fault. I'd go ahead and shoot the stuff. Does a once fired case from the hard to load group rechamber easily?

This all sounds bad to me. My tightneck chambers would NEVER be safe with an unturned saami spec case. Does the OP mean he has a rifle with a tighter than normal chamber (on the small side of saami spec) or does he have a deliberately planned tightneck chamber.

OP, my opinion is as follows: If you have a deliberately designed tightneck chamber STOP feeding anything that you have not miked, turned and assembled specifically for your chamber. It is russian roulette.

If you have a rifle that appears to have a tight chamber, get a cerrocast done (chamber casting).

Unless I misunderstand your posting, I think you may find real trouble with your current course of action.

I hope I totally misunderstood this post.
rc

I am with beeman on this. You may have a case problem. The headspace may be to long for the chamber. Or the bullet is jambing into the rifling very hard.

quote:

I am with beeman on this. You may have a case problem. The headspace may be to long for the chamber. Or the bullet is jambing into the rifling very hard.

+1

I`ve a tight necked 270 that one can barely press a bullet in the mouth of a fired case (can`t in some brass) and yet a chamber cast shows I`ve ~ 0.002-3" clearance with factory Remington brass. There is a bit of spring back present that makes for a false measurement if one just measures the OD of a fired new case.

I clean the necks up with a Forster neck tool but it isn`t really needed with most brass and doesn`t sound like you need to turn either.

I would cycle ammo through and separate into groups of easily chambered, snug and won't chamber. Mic necks on each group to see if there is a variance, then check SAAMI/CIP specs to see if the ammo is out of tolerance. If there isn't a consistent difference between each group then something else is causing the problem. Also check that the necks aren't bulged from an aggressive factory crimp. If the ammo is within spec and you want to shoot factory ammo, then have the neck opened up to the low side of spec. Also is there any chance short cases were used in that chamber that left a carbon build up where the very end of the neck is trying to fit?