Any tips out there on seating flat base bullets?

[Shaun Wayne]

Brother and I are reloading for our 22-250s.. We're having a hell of a time seating some flat base 55gr berger bullets for his rifle. Cant seem to get them to stay put like the BT Vmax do for mine. anyone know any tips or tricks? thanks!

 

[lennywd87]

Chamfer the ID of case neck if you haven’t already, slowly seat the bullet incrementally and give it a quarter to half turn each bit to ensure it seats straight in the neck. BTs are always going to be more convenient to seat. I’m sure some of these old timers might have more info.


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[B23]

What does the inside diameter measure compared to the outside diameter of the bullet your seating? Also, as stated above are chamfering the inside of the necks?

 

[Shaun Wayne]

We chamfered the cases but maybe need to do his a bit more next time

 

[ckrhtr]

I put a slight flare on the case mouth of my 20 practical and .204 when reloading flat based bullets, similar to what you would do with a pistol case . The last station of my press is setup with a crimp die.

 

[5 shot group]

I do the same as ckrhtr. Slight flare on the case, seat the bullet incrementally with a 180° degree turn half way through, then finish with a crimp.

 

[lennywd87]

I do the same as ckrhtr. Slight flare on the case, seat the bullet incrementally with a 180° degree turn half way through, then finish with a crimp.

@ckrhtr what diameter resized ball are you using or what’s your process for flaring? Do you just step up a single caliber and then ease it in a touch on each case neck?


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[lennywd87]

So .204 would be .224 and .224 would be .243 to flare the necks?


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[rayporter]

your neck diameter is too small on the case. a bushing die will cure the problem if you find the right bushing.

 

[5 shot group]

I use an expander made by Sinclair. Believe it was $35 for the die body and then $10-20 per mandrel. I just go a size up for what I'm loading and then just run the case up until it kisses the mandrel.

Luckily I only have to do this with 30-30, as everything else I shoot a boat tail in.

 

[lennywd87]

I haven’t seen any major issues myself after chamfering the necks. From .17-.308 caliber flat base bullets. You guys with your boat tails are just spoiled


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[B23]

I'd measure the inside neck diameter of your cases and compare that to the diameter of the bullet before I did anything. I would want to make sure the die isn't oversizing the necks or maybe the button is a little undersized.

 

[ckrhtr]

@ckrhtr what diameter resized ball are you using or what’s your process for flaring? Do you just step up a single caliber and then ease it in a touch on each case neck?


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I use a Sinclair neck expander and flare just enough to get the bullet to seat correctly. I use a .224
mandrel on my 20 Calibers
but only size it as much as I need to.

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[rayporter]

if you insist on using an expander button you can get pin gauges on amazon and put them in a collet style bullet puller to get a perfect fit - i would buy a couple as they are only 5 bucks. grind a point on the end and find the one that will get the fit you want

but the proper way is to get a bushing die and a couple bushings to get he right fit.

 

[potatojudge]

Any idea what your neck tension is currently?

 

[B23]

With all due respect if everything is right with your sizing process and brass prep, flat base bullets or not, you should NOT need to flare the necks to seat any bullet. If you do, then your sizing die is over sizing the necks and the button isn't able to compensate for it and that could be because your brass has thick necks or maybe you just got a bad die or the button is slightly undersized. Because necks have soooo much variance in neck thickness especially from brand to brand, bushing dies are your friend.

 

[Aaron Warpony]

Good advice here, high quality dies and press are very helpful too

 

[Cahunter805]

I use a VLD chamfer tool on all my brass. I’ve found it really helps with seating bullets and makes it much easier. I’d recommend trying one.

 

[cornfed]

Sounds to me like your just not holding the bullet straight till the seater stem has engaged . You can't just prop them there, as you're looking to start them as plum as possible by feel. 99% of Std green box FL dies with an expander button are capable of making straight ammo .
Most people with a concentricity gauge will tell you it's dusty from non use. As mentioned... Spinning the case 180 halfway thru the seating process is something to do, and I do with every screw in type seater die even the comp seaters. It's a sorta two stroke seating method that becomes second nature.
Neck turning the brass to a thinner more uniform thickness, and polishing 0.001 off the std expander buttons are ways to ease the FL sizing the brass as well as enough lube . All that ads up to less of chance of pulling the neck out of concentricity. YADA YADA YADA...