.45 ACP expanders and swaged bullets

After less than stellar results with my normally "very accurate" circa 1924 Colt Government Model at last weekend's 50 foot match, I noted that the barrel's grooves showed less than full contact with the old Star 185gr Swaged LSWCHPs which were substituted for the usual cast bullets. Pulled an unfired round apart and found that most of the bullet shank was 0.449" diameter. The taper crimp area was smaller yet. 
Dummy, me!

To make matters worse, all of my other spare expanders were no bigger than 0.450" diameter. Not feeling the desire to mess with the .45AR or various .45 Colt set-ups, I have ordered some expanders from Photo Escape. 

Little things....

That old Colt was built right. It locks up superbly and shoots very close to POA with 200gr bullets. It won't win a serious bullseye match but it was more than adequate for IDPA, etc., back when ammo was cheap. Figured it needed an outing or three during it's 100th year.

I tested 5 different brands of 45 acp brass. Same RCBS  sizer & expander. 

The spring back after expanding was very different between brands. 

Took from 45 pounds to over 100 to push the same bullet in to the case. 

Used my cast Lyman 200 gr bevel base bullets, sized at .452"

Those old swaged soft lead bullets should expand easily to fill the bore with a decent load. What was your load??

You'll want to get a larger expander for those swaged bullets.  Too much neck tension will swage the bullet to a smaller diameter then it'll never fit the bore correctly.  It doesn't take a whole lot of neck tension to hold it in place with a mild crimp.

The bullet does not swage down friend.  There isn't nearly enough hoop strength in the .010'ish inch thick brass, even with BHN 9 swaged bullets.  Stress calculations support this. My experiments with the 38 special reinforced the calculations (45 brass would be even more malleable).  Even with the thickest walled brass, it was always the brass that expanded by "nearly" the full amount of interference between the swaged bullet and ID of the brass, i.e. the bullet’s diameter plus 2x case wall thickness is going to be within .0005 in of the new OD of the case with its seated bullet.  This means that the bullet did not deform. This is also why, since the brass has passed its elastic capability, when you measure a fired case, it OD is halfway between sized and “with bullet loaded” diameters.  The brass permmanently deformed to give “some” of what was needed to get overtop of the bullet and “sprung” for the remainder.
Regarding your measurements, is it possible that dragging a bullet back out of a loaded case with a crimp, scraped material off of the bullet, giving you a false reading?  Anyway, my (and likely everyone else's) Dillon expander measures .447 and we're all putting tons of swaged bullets through them. 
Lastly, the "grip" created by the crimp alone (assuming you're trying one of your new, larger expanders) is not going to provide the complete burning (and accurate load, and cleaner gun...) that a healthy amount of bullet/case interference offers.
Good luck, but maybe look elsewhere for the source of your mediocre accuracy before you unpack those expanders; they may be returnable.

Try this: measure a swaged head, seat it in an underexpanded case, pull it and remeasure.

1) The inertia puller needs a tissue wad insert to prevent damage during extraction. 
2) examine the base edges for crescent shape wiping or other damage. This is a big problem. Jerry Keefer, in his wonderful postings stated each bullet must start by 1/16” by hand to give good precision.

Again I will heartily endorse AP PhotoEscapes powder thru expanders for flat base bullets.

A .45 Colt sizing/decapping die isn't a bad thing to try either. 

Re-sizing cases smaller than needed only adds to case shortening and fatigue from expanding them back out again.

As Bruce mentioned, measuring a new projectile, seating and crimping it, and then pulling and measuring it tells you all you need to know.

I shoot swaged lead exclusively in .45 and projectiles measure exactly as new after being pulled. I've had then swage down .0015" before making my own expander die.

Anyone done experimentation on the effect of 16000 psi on the expansion of the base of a swaged bullet deemed undersized in a cartridge case?

Outside diameters measured. Seat minus expanded = neck tension. .472" - .4698" = .0022" The (#) pounds to move the bullet were recorded using a bathroom scale. Made a wood lever to slowly apply pressure to the bullet nose. The highest pounds will be right before the bullet starts moving into the case.

Jim,

I believe that Dave Wilson has covered that with undersize vs properly sized projectiles in .32 cal.

I believe that there was a considerable difference in accuracy at 50 yards.

Side note: the OLD 45 Colt dies were set for 454 heads. The newer RCBS sizers that l measured were the same as current ACP dies. What is currently bigger and has worked well in the past ( as in before AP products) was the Hornady 454 Casull sizer.

Another aspect is increased gas flashover on undersize heads. Watch any slow motion video of firing. You’ll see a puff of smoke before the head exits the barrel, then you see the bullet exit fllowed by a large supersonic has expansion. This is gas flashover. It’s always present but has a greater erosive effect on undersize heads. Good luck

So the base of the soft lead bullet doesn’t obturate under the tremendous pressure to fill the barrel grooves.?

DA/SA wrote:Jim,

I believe that Dave Wilson has covered that with undersize vs properly sized projectiles in .32 cal.

I believe that there was a considerable difference in accuracy at 50 yards.

I don’t understand the slight undersize skirt issue on HB bullets.

james r chapman wrote:

DA/SA wrote:Jim,

I believe that Dave Wilson has covered that with undersize vs properly sized projectiles in .32 cal.

I believe that there was a considerable difference in accuracy at 50 yards.

I don’t understand the slight undersize skirt issue on HB bullets.

Agreed, there really shouldn't be an issue there. that's the purpose of the HB's.

I believe that there are many that claim the Remington .38 HBWC were the best due to the larger skirt diameter though.

Didn't Dave also find that the .38 HBWC shot better at 50 when using un-sized (as fired from that particular gun) cases?

james r chapman wrote:So the base of the soft lead bullet doesn’t obturate under the tremendous pressure to fill the barrel grooves.?

I'm not sure that it's all that tremendous in BE loads.

Lee claims 9800 psi for 4.0 BE/200 LSWC. Area of bullet base is roughly .160", so maybe 1500lbs pressure on a non-stationary surface. My one pistol shoots 2.8 BE/200 LSWC, so far less pressure.

Dunno, maybe that is enough to obturate, but questionable at 2.8 BE.

I like "more is better" in that if the projectile fits properly to start with, obturation can only help more!

james r chapman wrote:Those old swaged soft lead bullets should expand easily to fill the bore with a decent load. What was your load??

They should at bullseye pressures.

The tensile strength of pure lead is 2600 psi and BHN of 4.2.  Now typical swaged bullets have some Antimony in the mix so the tensile properties are higher but maybe double.  Whether or not the bullets will obturate is dependent on whether or not there is enough mass to create a “setback” condition in tge projectile.  In order to determine this you’d have to determine the acceleration of the projectile.  In pistol with fast powders and peaky pressures, I’m not certain.  

Some claim that the case “swaged” the bullet during seating.  This requires a “force balance” between the bullet and the case wall.  This requires specific analysis but I looked at what internal pressure would yield .010 thick wall Cartridge brass at a temper of H02 (Brinnell Hardness 55).  That pressure was 1800psi.  And 1800 was less than 70% of the tensile of pure lead.  If any swaging is happening it isn’t much.

jmoore wrote: Pulled an unfired round apart and found that most of the bullet shank was 0.449" diameter. The taper crimp area was smaller yet. 

Are you by chance using a Lee Factory Crimp Die?