450 bushmaster reloading issues

[Omidv]

I recently reloaded some bullets for my 450 bushmaster. The issue I’m having is that the cases don’t seem to be sizing down all the way like I think they should. I have a Lyman ammo checker and some of the sized brass falls in to where it should and some sticks up above about a 32nd of an inch or so. When loaded the rounds won’t hardly chamber and the ones that fit the ammo checker correctly fit the rifle perfectly. I’m not new to reloading but have never used hornady dies and wondered if anyone has heard of sizing issues with them on 450? Also this brass is once fired hornady brass fired from a bolt action. I then tumbled it and sized it. Case length is 1.692”
The ammo that does work I can get an amazing group with. Thanks for any help.

 

[snapbang]

Is all the brass from the same manufacturer??
Is the retainer nut holding the sizing die in place properly tightened????

 

[Omidv]

Yes all hornady once fired brass and I sinched the nut down after turning the die body a half turn down from contact at top of stroke, so the press lever kinda cams over at top. Some of the brass will drop right in.
View attachment IMG_3435.MOV

 

[MrTom]

Do any of the brass need trimming a hair?

 

[Omidv]

Do any of the brass need trimming a hair?

All seem to be right there at 1.690”
Some at 1.693 and they gauge perfect.

 

[Mike3888]

That’s strange some will and some won’t. Are you crimping?

 

[brad502a]

When seating the bullet, did you set the die to kiss and crimp the bullet? You need to close up the bell mouth.

 

[Omidv]

That’s strange some will and some won’t. Are you crimping?

Yes. Crimped to .475 the problem can be traced back to the sized brass before loading. These are also once fired hornady brass that are not fitting in the ammo checker after sizing. Some fall right in and some do not.

 

[brad502a]

Burrs on case mouth?

 

[Omidv]

Burrs on case mouth?

Nope it’s something with the case not sizing all the way down to case head.

 

[michiganmuzzy]

I never crimp 450bm to the .475, only a light crimp with a Lee factory crimper. @Omidv are you shooting these in a bolt gun or an AR?

 

[brad502a]

shellholder touching the bottom of the die?

 

[brad502a]

i load the 450 for both AR and bolt, FYI, using hornady dies. Is it possible that you are crushing the case with too much crimp? Sorry just reread the post about before loading please ignore the crimp comment.

 

[michiganmuzzy]

It sounds like you're saying they fit the case checker before sizing but not after. Get a new sizing die and see if that fixes the issue.

 

[Omidv]

I never crimp 450bm to the .475, only a light crimp with a Lee factory crimper. @Omidv are you shooting these in a bolt gun or an AR?

A bolt gun. I’m using the hornady 4 die set.

 

[Omidv]

shellholder touching the bottom of the die?

Yes touching and then a quarter turn down so the press cams over

 

[Omidv]

It sounds like you're saying they fit the case checker before sizing but not after. Get a new sizing die and see if that fixes the issue.

They don’t fit before but sometimes fit after sizing and sometimes they don’t fit after. If I load one that doesn’t fit then they don’t chamber

 

[HC]

I’d contact Hornday, it’s their brass and dies. Surely this isn’t the first time this has happened.

 

[michiganmuzzy]

Are you getting some bulged cases from loading them too hot, maybe? Or if they were someone elses maybe that happened. I know i load mine pretty stout for my bolt gun with 250 and 300XTP mags.

 

[Omidv]

Are you getting some bulged cases from loading them too hot, maybe? Or if they were someone elses maybe that happened. I know i load mine pretty stout for my bolt gun with 250 and 300XTP mags.

They are once fired factory hornady ftx brass. I’m only loading to get hornady factory fps. That way if I ever want to use factory ammo I can switch back.