boolit setback experiments

[guy_with_boolits]

I did a few experiments to measure the force required to push a 45ACP boolit into the case. Unfortunately all I had today was ALOX'd and unlubed boolits. I will do PC'd boolits later. There are also several combinations of PC, ALOX, and case prep I'd like to measure as well.

The test setup is a drill press with a center punch in the chuck. The center punch is small enough in diameter to fit inside the boolit hollow point noise (MP-452-200).

The loaded round is placed on top of a bathroom scale which is on the drill press platform. As the center punch is pushed on the boolit, pushing it into the case, the scale measures the force. Since its pushed inside the hollow point, the nose isnt distorted and I can measure COAL accurately.

I did three tests:

Boolit is MP-452-200 with circular hollow point with alloy between 9 and 11bhn probably

Cases are federal with small primers range pickup (since its likely once-fired)
3 different cases and 3 different boolits were used for each test
All cases were full length sized, decapped, and flared using the powder disc expander.
Crimping of any type was not performed. Flare remained. Boolit was seated then immediately put on the fixture to measure setback force.

NO LUBE, AS-CAST BOOLIT
Seat to 1.175"
No crimp

Case 1 265lbs
Case 2 250lbs
Case 3 280lbs

Confirmed no change in COAL at 200 lbs

ALOX'd UNSIZED boolit (approx 0.453" diameter)

Case 1 150lbs
Case 2 175lbs
Case 3 150lbs

Confirmed no change in COAL w/100 lbs

NOE 0.452" expander used after flaring (0.330" deep)

Case 1 50lbs
Case 2 80lbs
Case 3 70lbs

Confirmed no change in COAL w/40 lbs

So it would appear that, with ALOX, the 0.452" NOE expander is a little on the loose side, at least for me.

I also have a NOE 0.451" NOE expander I can try, as well as PC boolits.

I could also drill holes in the primer pockets of the cases, so I can carefully pull the boolits out and compare their before and after diameters.

[Winger Ed.]

That's interesting.
However: My world is a much simpler place.

If a revolver case is noticeably roll crimped into a boolit grove,
or I can't mash a boolit down into a taper crimped case with my thumb---- I call it good.

Then, I go into 'mass production for a batch' mode,
and after that, I start working on how soon I can get to the range and shoot 'em.:bigsmyl2:

[guy_with_boolits]

That's interesting.
However: My world is a much simpler place.

If a revolver case is noticeably roll crimped into a boolit grove,
or I can't mash a boolit down into a taper crimped case with my thumb---- I call it good.

Then, I go into 'mass production for a batch' mode,
and after that, I start working on how soon I can get to the range and shoot 'em.:bigsmyl2:

I got to the range almost every day so I need something to do besides shoot

[Winger Ed.]

I got to the range almost every day so I need something to do besides shoot

You're my new hero.
I have to plan my escape a day or so in advance,
bribe the guards, go out through a Hogan's Heros tunnel, come up in a tree stump, and make a 25 mile trip.[smilie=2:

[Bazoo]

My world is simpler too. I just made my first batch with a new mould, the RCBS 45-201-SWC. I loaded some dummies, sized to .452 and lubed with 50/50. I then proceeded to cycle them through my 1911 half a dozen times. The noses were deformed slightly but they didn't setback any. They plunk and cycle. Next will likely be some bullseye loads to test for accuracy and function. OAL will be 1.215 for now. Just a smidgeon of driving band showing.

[Wayne Smith]

Why uncrimped? I crimp all my ACP rounds - just loaded 100 rounds the other night. Same boolit you are using, and taper crimped all of them.

[Hossfly]

I’ve tested some 9mm, at 50# with a very accurate electronic scale, on the bench with my hand and paint stirring stick on top of the round. To test if my crimp was good enough, results = good enough, no movement detected.

Measured before and after the test.

[popper]

In SA pistols, proven that factory ammo, setback is from chambering the same rnd many times. In revolvers, bullet moves forward. Interesting test and I can say PC increases push required IF neck tension is proper.

[guy_with_boolits]

Why uncrimped? I crimp all my ACP rounds - just loaded 100 rounds the other night. Same boolit you are using, and taper crimped all of them.

just for the test...one more variable

[mdi]

Now that we know how much pressure it takes to push a specific bullet into a specific case, we now need to find out how much pressure is exerted on a bullet nose when feeding. Would need a few tests with different guns (1911, Glock, S&W, etc.).

BTW; in my experience crimping on a semi-auto round is unnecessary and as often as not, can be detrimental. Taper crimping is so subjective/personal, that even when measuring there are a few added variables. I'm in the "Deflare only as Neck tension is enough" camp. Testing without "crimping" will give much better indication of neck tension variables...

[charlie b]

I've fired too many rounds to count through a 1911 with no crimp. Only setback I had was when the round jammed hard into the hood or ramp of the barrel (FTF). Those rounds were not fired.

These days I do taper crimp, just barely and just because I have that space free on the press :)

Back in the old days when I pan lubed bullets I did notice another problem. If I was too fast with the seating stroke on the press the rounds would come out too long. Seemed the air pressure in the case was enough to push the bullet back out a little. Leaving the ram at the top of the stroke for a second or two fixed the issue. All the extra lube made the bullet too slippery :)

[onelight]

Not to disagree with anything anyone has posted about not using any crimp you guys know what works for you.
But there are many variables that come into play to prevent setback and functioning , we have people that use and recommend oversize expanders and the depth the case is expanded , there are different thicknesses of brass different size bullets to seat and different length cases to be dealt with , we have had a post recently to use unsized brass and let the crimp hold the bullet . An answer can be simple to someone with years of experience in the right combination I don't doubt most all these suggestions work for the guys that post them , but the wrong combinations of these suggestions could be dangerous without explaining details that differ from what a reloading manual instructs for standard practices for safe reloading. Even not shooting a round that has jammed , is making the assumption that the person that reads the post would do it the same way. We all were new at one time we forget how much we didn't know.
Just my opinion .

[popper]

Agree it is something reloaders need to consider. If it moves when nose hard push against the table top it doesn't get fired.

[charlie b]

I made the comment about not firing a jammed round to hope to influence those who have similar failures. I don't want to see someone fire a round that could damage them or their pistol.

[guy_with_boolits]

would be very easy for me to measure force to push in, and push out, with a crimp and without..to see what the difference is

[Three44s]

You're my new hero.
I have to plan my escape a day or so in advance,
bribe the guards, go out through a Hogan's Heros tunnel, come up in a tree stump, and make a 25 mile trip.[smilie=2:

It takes a revolver guy to come up with one as good as THAT!

Kudos!!

Three44s

[Three44s]

would be very easy for me to measure force to push in, and push out, with a crimp and without..to see what the difference is

Yes, I think that lube or PC and a taper crimp is where it’s at .....

Good work!

Three44s