I need some help in the loading room

[Matt_3479]

I’m a little stumped. I am running Lapua 6br brass in my 6bra. The brass was fire formed and now has 6-7 firings of lighter-moderate load. 105’s running around 2880fps. I did my regular reloading session to it out to shoot and I couldn’t chamber it without absolutely slamming the bolt to the point I bruised my hand. I only fired a few rounds before I decided to stop.

I got home checked the length it was fine. I pulled the bullet and checked the shoulder bump it’s fine, I pulled them all at this point. I resized the brass and it loaded just fine. I sat a bullet and I can’t get it to chamber. I was about to get 5 out of 10 to work. Is it possible for brass to flow to the point were you need to start turning necks! I’ve never heard of it or thought of this before. Overall length is actually shorter than it needs to be by a few thou as well.

 

[dgeesaman]

A few thou is not enough clearance on overall length. If you have carbon building up in the forward part of the chamber neck, it will form a taper that wedges against the end of your brass.

If you have a borescope (Teslongs are cheap!!) load a piece of bare resized brass and peek in from the muzzle end to see how the clearance is.

As for loaded neck diameter growing, what does it measure?

 

[JMayo]

I'm fire forming some that have allot of runout, aka crooked. I'm having to ram the bolt hard to get it to close.
I thought my bullet seating might be too long... But that wasn't it.
it was a Crooked neck. They eject then re chamber fine after shooting them.

 

[Matt_3479]

A few thou is not enough clearance on overall length. If you have carbon building up in the forward part of the chamber neck, it will form a taper that wedges against the end of your brass.

If you have a borescope (Teslongs are cheap!!) load a piece of bare resized brass and peek in from the muzzle end to see how the clearance is.

As for loaded neck diameter growing, what does it measure?

Sorry I meant a few thou short of minimum trim length. I know it’s not the unloaded resized brass lengths as they drop right into the chamber perfectly fine. Barrel is clean as a whistle as I thought that too. I checked with a borescope and cleaned it anyways and it’s good to go. I pulled my barrel and been resizing and dropping brass in perfectly.

Seat the bullet and bam, won’t go in. The only thing I can think of is neck diameter is too tight now. But I’ve never heard of it or thought of it for previously. For 6-7 firings 0 issues now it won’t load. Is it possible for brass to flow and grow neck thickness as the length is fine.

I'm fire forming some that have allot of runout, aka crooked. I'm having to ram the bolt hard to get it to close.
I thought my bullet seating might be too long... But that wasn't it.
it was a Crooked neck. They eject then re chamber fine after shooting them.

It’s not fire forming loads those. These have all been fireformed. Like I said they have 6-7 firings on them and never had a single issue and now I can’t chamber

 

[Mulligan]

In my rifles, brass grows in both length and thickness.
I find I have to turn the brass again after a few firings.
CW

 

[rwj]

Inspect the cases for evidence of where they are contacting the chamber wall. If you have to slam the bolt handle to chamber a round, I’d suggest stopping at that point until you identify and correct the issues.

 

[JMayo]

Sorry I meant a few thou short of minimum trim length. I know it’s not the unloaded resized brass lengths as they drop right into the chamber perfectly fine. Barrel is clean as a whistle as I thought that too. I checked with a borescope and cleaned it anyways and it’s good to go. I pulled my barrel and been resizing and dropping brass in perfectly.

Seat the bullet and bam, won’t go in. The only thing I can think of is neck diameter is too tight now. But I’ve never heard of it or thought of it for previously. For 6-7 firings 0 issues now it won’t load. Is it possible for brass to flow and grow neck thickness as the length is fine.


It’s not fire forming loads those. These have all been fireformed. Like I said they have 6-7 firings on them and never had a single issue and now I can’t chamber

I was saying they might be crooked .....

 

[17cal Fan]

Not enough case lube inside the neck. Expander ball is pulling against shoulder angle and changing the shoulder angle when drawing expander ball back out of the case. It takes very little force to cause this. It can be measured with a RCBS precision mic or a Digital Headspace Gauge from Innovative Technologies (larrywillis.com).

I don't even know how long I've had my digital headspace gauge but it's a lot cheaper than buying even 2 precision mics. I use mine constantly and is one reloading tool that I would not be without.

 

[Matt_3479]

I was saying they might be crooked .....

I don’t believe I understand what you’re trying to say then? I’m unsure how the case neck is crooked when after sizing it’s 100% fine. The second I seat a bullet its off?

 

[Matt_3479]

Not enough case lube inside the neck. Expander ball is pulling against shoulder angle and changing the shoulder angle when drawing expander ball back out of the case. It takes very little force to cause this. It can be measured with a RCBS precision mic or a Digital Headspace Gauge from Innovative Technologies (larrywillis.com).

I don't even know how long I've had my digital headspace gauge but it's a lot cheaper than buying even 2 precision mics. I use mine constantly and is one reloading tool that I would not be without.

I don’t use an expander ball so it’s not that either.

 

[Matt_3479]

In my rifles, brass grows in both length and thickness.
I find I have to turn the brass again after a few firings.
CW

So my chamber is tighter then usual but not so tight that it needs to be turned off the hop?

 

[Toejoe12]

Take one of the cartridges you seated a bullet that wouldn’t chamber, pull the bullet but do NOT resize the case. Try and load it again without the bullet. if you have difficulty it is the neck diameter.

 

[old codger]

If a sized but not loaded round will chamber easily you have a bullet seating problem not a sizing problem. Maybe insufficient neck chamfer and the bullet is seating hard and expanding the shoulder a touch.

 

[Coyotefurharvester]

If sized brass chambers perfectly, there would only be 0.001-0.003 increases in neck diameter when a bullet is seated. If a bullet will slip into the neck of fired unsized brass, I doubt it is a neck thickness issue. ^^^^ seating problem. Standard seating die, very easy to put a crimp on a bullet that pushes the body/shoulder diameter out.
I have 3 minimum SAAMI spec (custom reamer) chambered rifles, all will slip fit a bullet into fired cases. Cases that have been fired multiple, annealed, times. Haven't seen a factory rifle that isn't the same way.

 

[Toejoe12]

If sized brass chambers perfectly, there would only be 0.001-0.003 increases in neck diameter when a bullet is seated. If a bullet will slip into the neck of fired unsized brass, I doubt it is a neck thickness issue. ^^^^ seating problem. Standard seating die, very easy to put a crimp on a bullet that pushes the body/shoulder diameter out.

Where did you read a bullet would slip into the neck of fired unsized brass easily

 

[J.d. Popkes]

Small base die. Get a 308 small base die. Run it through that. If it fixes it you’ll be good for another few cycles, reuse as needed.

 

[Matt_3479]

If a sized but not loaded round will chamber easily you have a bullet seating problem not a sizing problem. Maybe insufficient neck chamfer and the bullet is seating hard and expanding the shoulder a touch.

it’s not chamfer either, I checked that for sure. The bullet seating is no different than before. It feels fine. Very little pressure.

 

[Matt_3479]

If sized brass chambers perfectly, there would only be 0.001-0.003 increases in neck diameter when a bullet is seated. If a bullet will slip into the neck of fired unsized brass, I doubt it is a neck thickness issue. ^^^^ seating problem. Standard seating die, very easy to put a crimp on a bullet that pushes the body/shoulder diameter out.

I know that but I’m wondering if brass flow can instead of growing neck length wise, grow them in thickness making my no neck turn chamber into a now neck turn chamber due to brass neck thickness growth. There’s no crimping on the bullet pushing the shoulder out. I pull the bullet and check with my shoulder bump gauges and the brass doesn’t move. But it still won’t chamber. The more I eliminate the more it’s leading me to believe it’s the neck

 

[ronemus]

In my rifles, brass grows in both length and thickness.
I find I have to turn the brass again after a few firing

^^^ this - can be remedied by using an expander to set the ID and neck turning for removal (usually appears as a raised band at the neck-shoulder Junction).

 

[ronemus]

I know that but I’m wondering if brass flow can instead of growing neck length wise, grow them in thickness making my no neck turn chamber into a now neck turn chamber due to brass neck thickness growth.

Yes, especially if the brass isn't closely fitted to the chamber. As suggested above, measure it! You should have a ball mic; if you don't, get one.