.45 acp reloading question bullet walking forward

growr · Jun 2, 2016

A dear friend of mine has a 625 PC revolver and is using his Dillon 550b with RCBS dies...The problem that he is having is that no matter what bullet/ casing/ amount of crimp used after firing 5 rounds the 6th round has up to 30-40 thousandths forward travel.

Not enough to lock up the cylinder but still enough to change things.

Now when I reload .45 acp on MY 550 with Dillon dies, no matter what bullet/casing/amount of crimp used I don't have this as an issue.
The only constant in his set up verses mine is the die....

Can anyone shed some light on why this is happening. Do you think that the REAL problem is in his RCBS carbide dies?

We are shooting in an Action Pistol match this weekend and I am going to loan Jesse my dies and shellplate to see if the problem goes away.

I am baffled and am turning to the forum for fresh ideas.

Randy

PS. He has been trying different amounts of crimp with lead/plated/coated/FMJ bullets as he is experiencing severe leading after 12 rounds. I think that a call to Smith is in order....What do you all think?

OKFC05 · Jun 2, 2016

First suspect is the expander die size or adjustment thereof. No amount of crimp will compensate for an overexpanded case. I would start by measuring dies and the expanded cases from each.

I really like the Dillon dies for avoiding this kind of problem.

StakeOut · Jun 2, 2016

Plated and coated shouldn't cause any leading.

Do you stop to measure OAL and not shoot the 6th round?

How hot are they loaded?

What brought this phenomenon to the shooters attention if it didn't stop the revolver from firing?

I'll be at the range later today shooting my 45 revolvers(625-2,25-2) with my hand loaded 200gr Berry's plated SWC and Hornady 200gr LSWC over 4.0gr of Bullseye.

I'll add a dial caliper to my shooting bag.My 45acp OAL is usually set at about 1.240

Calliope · Jun 2, 2016

Most likely he's over expanding the cases prior to bullet seating.

bigggbbruce · Jun 2, 2016

growr said:
I think that a call to Smith is in order....What do you all think?

No.. telling them about your reloads voids warranty.

As mentioned above.. bell the case as little as possible to get the bullet started for seating.

Get brass that has better neck tension to start with. I find certain makes have much more tension than others.

If no bullets are falling out or locking up the gun. Keep shooting.

Bruce51 · Jun 2, 2016

Is he using a FCD? This will resize both the case and the bullet reducing the bullet diameter with a loss of case neck tension.

Even though a lot of users swear by the FCD I have found if the case is tight and I used the die the bullet will be undersized.

Is he using mixed brass? Remington brass is known to be thin. Winchester is generally thicker brass. One can usually feel the difference in brass thickness when resizing.

The bell has already been mentioned as a possible cause. Also check the bullet diameter just to be sure.

BLM

growr · Jun 2, 2016

StakeOut said:
Plated and coated shouldn't cause any leading. They shouldn't...but they are

Do you stop to measure OAL and not shoot the 6th round?
That is correct

How hot are they loaded?
200 gr and 230's with 6 gr. of Unique not a hot rod at all

What brought this phenomenon to the shooters attention if it didn't stop the revolver from firing?

He fired five and then had to do a reload...when he picked up his moon clip he noticed the bullet walking forward, then decided to actually test this with his calipers

I'll be at the range later today shooting my 45 revolvers(625-2,25-2) with my hand loaded 200gr Berry's plated SWC and Hornady 200gr LSWC over 4.0gr of Bullseye.

I'll add a dial caliper to my shooting bag.My 45acp OAL is usually set at about 1.240

Randy

PS. Will ask him about over-belling the case mouth....

fredj338 · Jun 2, 2016

I use quite a bit of bell on my 45acp, Dillon dies, lead, coated, plated, jacketed, I never have an issue with the bullet walking. I suspect the powder thru is over size. I do know with RP brass, I must use 0.452" bullets or neck tension goes to krap & no amount of crimp fixes that.

Rule3 · Jun 2, 2016

Clearly a problem with the Dillon Press.

Does he shoot these same loads in a semi auto?

If so does he experience set back.?

You mention "any bullet" such as?? Plated, FMJ. Lead?? how many different ones have actually moved?

Over flare is a big variable. check there.

Not even gonna go near crimping.

cmj8591 · Jun 2, 2016

Spend $20 and get a taper crimp die. It won't matter how much you expand the mouth, once you run the round into the taper crimp die it will tighten the cases' grip on the bullet. Or, if you are only using the ammo in a revolver then set your seating die to finish with a heavy roll crimp. Here's the rub with this method: If you are using jacketed bullets, too heavy of a roll crimp might bulge the case and make it difficult to chamber and you won't be able to use the roll crimped ammo in an auto loader. I use a taper crimp die. it's clean, easy and holds the bullet tight.

Calliope · Jun 2, 2016

It won't matter how much you expand the mouth, once you run the round into the taper crimp die it will tighten the cases' grip on the bullet.

That's not true. Bullet tension is the primary hold on the bullet, crimp does little to hold the bullet in place. Over crimping can actually cause reduced bullet tension because the bullet doesn't spring back when crimped, but the case does.
Look at factory .45 acp ammo, no crimp at all.

noylj · Jun 2, 2016

Flare is not expansion. One flares the case mouth so the bullet can sit on/in the case and expansion takes the sized case ID (say 0.443") to 0.001-0.002" under bullet diameter (say, 0.450").
The "best" solution is to buy jacketed .45 Colt bullets with cannelures or lead bullets with crimp grooves and use a ROLL crimp. That what is needed for revolvers.
Dillon, RCBS, Hornady, Lee, Redding: all make excellent dies. Each person may have a preference, but they all do the job.
So, check the expander diameter and the case ID before and after expansion, as recommended above, and let us know.

Leading in a revolver is caused by the same thing as in a semi-auto--poor bullet fit.
For a revolver, you need the bullets to be a snug slip-fit in the cylinder's throats and be at least 0.001" larger than the actual measured barrel groove diameter. Have you checked dimensions?
If you are getting leading with plated or jacketed, you have a real problem.
Some revolvers have under-sized throats and/or over-sized groove diameters and simply can't shoot lead bullets. A bullet squeezed down too far in the throat can not fill and seal the bore if groove diameter exceeds the bullet's diameter.

cmj8591 · Jun 2, 2016

Calliope said:
That's not true. Bullet tension is the primary hold on the bullet, crimp does little to hold the bullet in place. Over crimping can actually cause reduced bullet tension because the bullet doesn't spring back when crimped, but the case does.
Look at factory .45 acp ammo, no crimp at all.

The whole point of using a taper crimp die is to increase the tension holding the bullet in the case while maintaining the ledge created by the case mouth so proper head space is maintained. It does this by pressing the case against the side of the bullet to create tension. Most factory 45acp ammo uses a taper crimp. It is very slight but it is there. Roll crimps push the mouth of the case into the bullet by rolling it over into the bullet. It only applies pressure at the point where the rolled over case mouth contacts the bullet. Usually, a roll crimp requires a cannelure or some type of crimp groove on the bullet to engage the crimp. Roll crimps are used with cartridges that headspace on their rim or shoulder. Straight walled, rim less cases like the 45acp don't use a roll crimp because it can create excessive headspace.

Bruce51 · Jun 2, 2016

Really!

cmj8591 said:
The whole point of using a taper crimp die is to increase the tension holding the bullet in the case while maintaining the ledge created by the case mouth so proper head space is maintained. It does this by pressing the case against the side of the bullet to create tension. Most factory 45acp ammo uses a taper crimp. It is very slight but it is there. Roll crimps push the mouth of the case into the bullet by rolling it over into the bullet. It only applies pressure at the point where the rolled over case mouth contacts the bullet. Usually, a roll crimp requires a cannelure or some type of crimp groove on the bullet to engage the crimp. Roll crimps are used with cartridges that headspace on their rim or shoulder. Straight walled, rim less cases like the 45acp don't use a roll crimp because it can create excessive headspace.

I'm going to disagree just a little on this statement. Bullet tension is set by resizing the case and using a bullet larger than the inside diameter of the resized case. The taper crimp simply removes the bell and allows for proper headspacing on the case mouth.

If we relied on taper crimps to provide case neck tension then all of our reloaded bullets would be too loose. The taper crimp is only moving a small amount of the brass.

It is the resizing die and the varied thickness of brass which keeps a bullet tight in the case.

Sometimes the harder one tries to taper crimp a bullet tight the looser the bullet will be.

Any extra crimping will reduce the bullet diameter with a loss of case neck tension on the bullet.

Same with roll crimping. If it is overdone then cases can bulge,bullets can get loose and cartridges will not chamber.

Try to load some bullets, without resizing and taper crimp them. It won't work. Cases must be resized for a good reason. They hold the bullet tight.

I see that Calliope also explained this as well.

I'm happy to see another spot on reloader posting.

BLM

fredj338 · Jun 2, 2016

Calliope said:
That's not true. Bullet tension is the primary hold on the bullet, crimp does little to hold the bullet in place. Over crimping can actually cause reduced bullet tension because the bullet doesn't spring back when crimped, but the case does.
Look at factory .45 acp ammo, no crimp at all.

I agree & disagree. No, taper crimp cant hold a bullet from moving forward. The taper goes front to back, not possible. I disagree on factory ammo not being crimped. I've salvaged too many factory ball rds & found they are often over crimped ime.

alwslate · Jun 2, 2016

No really significant details provided in the OP. What bullet design?
Does it have a crimp groove? What type of crimp is being used? If you
want trouble free rounds in a revolver use cast bullets with a crimp
groove or a shoulder to crimp over and apply a good roll crimp.

BLUEDOT37 · Jun 3, 2016

growr said:
A dear friend of mine has a 625 PC revolver... he is experiencing severe leading after 12 rounds.

How new is his 625PC? My new one had a barrel constriction (frame thread choke?) where it is screwed into the frame. Is his leading starting there, mid barrel?

As already mentioned there are several possible reasons for the jump crimp: thin brass (Remington), poor case-bullet tension due to under-sizing (diameter too large) by the depriming/sizing die, inconsistent bullet diameter/sizing along bearing surface, etc. He'll just have to eliminate one at a time to find the cause.

.

H Richard · Jun 3, 2016

I've been reloading 45 ACP for over 30+ years for both 1911 and revolver, and have never had this problem. I use a separate taper crimp die, put .003 crimp on either cast or jacketed bullets and it holds just fine.

moxie · Jun 3, 2016

Calliope and Bruce Lee M have explained it perfectly.

Luke Duke · Jun 3, 2016

I don't expand my brass unless I'm using lead bullets. Put a light chamfer with my chamfering tool , never smashed a case and get a tight bullet fit. give a slight taper crimp. Try to beat one out with a bullet puller. You'll work at it.

.45 acp reloading question bullet walking forward

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