Cant fit a bullet down a fired case. Is this okay? HBN Causing Issues?

[Deviant]

This is a 2 part question so bare with me.

1. I have a custom 6.5 GAP that I made brass for from Bertram 7mm SAUM. I necked it down trimmed and turned the necks to .014 then fire formed all cases. The reamer specs are .2962 neck and a loaded case measures .2925 but after firing i cannot push a bullet into the case with my bare hands. Is this okay or do I need to take more off of the necks? I can usually fit a bullet easily into a fired case on my other custom rifles and this is my first time using Bertram brass. I have been bumping the shoulder .0015 with a Whidden FL die with the expander removed and then using a Sinclair expander mandrel afterwards.

2. I am also having issues seating bullets and shaving copper off especially with HBN coated 143 ELDX bullets. I switched to HBN coated Berger 140 Elite Hunters now and it is not as bad but I still shave a copper sliver off occasionally. I tried switching to a differentI chamfer and deburing tool with no luck so I thought it was the HBN causing this but maybe its the Bertram brass being so hard? I just received my AMP MKII annealer and will try it out when I have burned through the loaded rounds. I have only used HBN on one other rifle recently and the 130 Bergers seat fine in that gun but it is in Nosler brass.

Thanks AL

 

[ar10ar15man]

a anneal the brass
b size the brass just under say 1-3 thou
chamfer the in side of the necks
in this 3 is a great source of shaved bullets.
my guess is your chamber ain't what you think it is or you mis-measured something.
even in a tight benchrest gun the bullet will go in the neck after firing, so you have a math problem somewhere.

 

[cohunt]

What is the ID of your neck after sizing?

How many times loaded is the brass? Did you anneal it? Did you chamfer the necks?

The neck should be expanding to allow a bullet in a fired case-- you started the dimensions of the reamer but have you actually measured the chamber to see if it's the same as the reamer print?

What is the OD of a fired case?

Math shows chamber to neck clearance to be .00185"

 

[Deviant]

What is the ID of your neck after sizing?

How many times loaded is the brass? Did you anneal it? Did you chamfer the necks?

The neck should be expanding to allow a bullet in a fired case-- you started the dimensions of the reamer but have you actually measured the chamber to see if it's the same as the reamer print?

What is the OD of a fired case?

Math shows chamber to neck clearance to be .00185"

Brass has been loaded twice. Have not annealed yet but I just received my AMP MKII yesterday. Is a chamber cast an accurate enough way to measure the chamber? I will have to measure a fired case again as I don't Remember the measurement.

 

[Deviant]

a anneal the brass
b size the brass just under say 1-3 thou
chamfer the in side of the necks
in this 3 is a great source of shaved bullets.
my guess is your chamber ain't what you think it is or you mis-measured something.
even in a tight benchrest gun the bullet will go in the neck after firing, so you have a math problem somewhere.

I must be missing something here then unless my chamber is smaller than the reamer print. neck thickness =.014 + .014 + bullet diameter of .264 = .292 When I measure a loaded round it is .2925 which is very close to what my math says it should be unless I am figuring something wrong I should have .0037 clearance if the reamer print is correct. .2962 - .2925 = .0037 unless i'm missing something.

 

[Deviant]

ID of neck after sizing was .262

 

[ShtrRdy]

It sounds to me like the neck area is too hard. Annealing time.

 

[can1010]

need to know neck OD of fired case before sizing.
I believe there are two different neck dia. a turn and no turn. I believe the original was a .292 neck you might have print of one and reamer of the other.

 

[Deviant]

The fired cases measure .2955 about a third of the way down the neck. But at the very top rim of the neck at the opening it measures .291. What length should I be trimming my brass? I did 2.015. Here is a picture of the reamer

print I believe was used.

 

[can1010]

try 2.005 trim length, 2.015 max. turn necks to .0135.
don't like that case mouth is .291 should not be that tight unless it is crimping the case because it is to long.
grizzly industries is ptg reamer and not always ground to the print

 

[can1010]

and definitely anneal your brass Bartram is pretty hard brass. I use a lot of their brass and always anneal after prep and before first shot

 

[Deviant]

and definitely anneal your brass Bartram is pretty hard brass. I use a lot of their brass and always anneal after prep and before first shot

Will do thanks.

 

[22Kreedmire]

I must be missing something here then unless my chamber is smaller than the reamer print. neck thickness =.014 + .014 + bullet diameter of .264 = .292 When I measure a loaded round it is .2925 which is very close to what my math says it should be unless I am figuring something wrong I should have .0037 clearance if the reamer print is correct. .2962 - .2925 = .0037 unless i'm missing something.

Your total neck clearance is .0037". But you have to divide that by 2 for clearance on all sides. .00185 is your clearance on all sides. Kinda like going from a 33" tire to a 35". Yeah it's 2" bigger but you only get 1" more ground clearance. That being said. .0015" on all sides is usually enough clearance and you can slide a bullet into the case after firing or even drop it right in and it'll slip through .

 

[redneckbmxer24]

Are you chamfering the case mouths? Shaving jackets going in tells me you're not, or not enough.