[WalterMitty]

I belong to that school of thought that doesn't believe crimping helps setback very much and too much crimp hurts a lot.

In sized brass with correct diameter bullets the brass wall provides the lions share of the support. Look at a freshly sized brass wall and look at a loaded round. Is the brass "bulged" where the bullet is seated? For the bullet to go deeper in must "resize" the brass; which should take some force.

However, if you over crimp (think about the profile in the crimping die and what it is doing) you can actually deflect the brass and loosen the grip on the bullet.

Of course, this discussion makes the assume that the problem isn't a feeding problem where the bullet is impinging on the feed ramp (or something else) at too steep an angle and is being driven home by a 20# jackhammer spring. Nothing short of LockTite Red can help that situation.

Oh yeah, I forgot your other question. Reduced OAL increases pressure. In extreme examples this could be bad.

[This message has been edited by WalterMitty (edited 11-17-2001).]

 

[doctor j]

What brand of cases are you using? I've had some problems with loose bullets in R-P cases, even with a healthy factory crimp (with Lee Factory Crimp die). As I understand it, the R-P case walls are a little thinner than those of other headstamps. This could be your problem.

 

[Wit]

I had similar problem when using Rainier (sp?) copper plated bullet in my miscellaneous brass. Once changed to lead bullet, the problem was gone. I also found Federal brass to be more consistent than the R-P. I'll try to use only Federal from now on.

 

[Sammy Fan]

I use mostly miscellaneous once-fired brass. I notice this problem with almost any brand. I agree with WalterMitty that if the cartridge impacts the ramp at an awkward angle with force, the bullet will set back. I had FTF problems due to nose dives and managed to solve the problem somewhat by polishing and contouring the ramp. Now feeding is no longer a problem, but the cartridge will still dive down towards the ramp at first. This impact will definitely shorten the round.
But how much of this set back is acceptable? and how will it affect accuracy?

 

[Walking Point]

Try a longer OAL. Shorter rounds normally cause a lot of what you're describing.

Although SWCs vary in length, 1.250" will feed much better than 1.210". Somewhere in between may just be perfect.

Crimping with a .45 should do no more than remove any belling in the case mouth. As with all calibers, the case neck tension is what holds the bullet in place. Since brass springs back, a heavy crimp does nothing more than loosen things up since the bullet will be deformed and cause the problem to be worse. Roll crimps are a different story to a degree, but case tension is the key.

Wit notes that cast bullets solved his problem. This is likely due to the additional neck tension resulting from those cast bullets being .001 - .002 bigger than the jacketed.

 

[RMark]

.460" crimp is too much in my opinion. You are probably deforming the bullet! I crimp no more than .468" at the case mouth. I have never seen "factory" ammo crimped at .460"
Just my 2 cents....

 

[KLN]

Bullet set-back in the case can be dangerous, and must be fixed.

The situation is made worse by ammo that is too short, resulting in "nose diving" into the feed ramp, but properly reloaded ammo will not set back in the case even if it takes a dive.

The problem is rarely caused by the sizing die being too large. I have not seen one yet that was so. The problem is an expander that is too large. Expander plugs have two diameters. The first enters the case and expands well into the case, and the second flares the case mouth. It is the first part of the expander that is the problem. It is expanding the case too much, which results in a round with inadequate case tension.

The solution is to chuck the expander rod in a drill and run it over abrasive cloth or paper until it is the correct diameter. The portion of the expander that flares the case mouth should not be reduced -- only the first part that expands well down into the case.

The expander is small enough when all rounds, including those in thin Remington cases, have an hourglass appearance. There is a noticeable reduction in case diameter below the point where the bullet stops in the case, and you cannot force the bullet further in by pressing the loaded round by hand nose down on the bench.

Presumably the expander could be made too small, but I have not seen it happen. Even with dramatically hourglass shaped ammo -- the result of a very small expander diameter -- accuracy did not seem to be hampered.

It seems odd that die makers sell dies with an expander that is too large, resulting in potentially dangerous ammunition, but it is common. Even the Dillon expander plug for the powder die is sometimes too large, depending on the cases being used.

Pistol ammunition reloaders should understand this situation well. It is important.

 

[Walking Point]

All ammo will set back in the case under the right (wrong?) conditions.

I've seen factory ammo do it many times in handgun and rifle rounds.

Do not screw around with the expander unless all else fails. No need to ruin a die for no reason.

 

[Jim Watson]

I am with KLN. Bullet setback can lead to jams if the round does not bounce into the chamber and high pressure if it does. Expander plugs are not very expensive. They should mike noticeably smaller than the bullet. If one doesn't, turn it down. In extreme cases I have loaded ammo with a case mouth flaring tool that does not expand over the bearing surface at all. If that did not fix the problem, I concluded that the brass was thin, the bullet undersized, or the sizing die too big. I have seen all such conditions at one time or another. I have two sizing dies that I use only to load cast bullets with because they do not give enough grip to smaller, smoother jacketed bullets.
The "coke-bottle" appearance below the base of the bullet is normal and desirable, a sign of good bullet pull.

Your OALs do sound a bit short, but there are a lot of SWCs around. Do you see some bullet shoulder ahead of the case mouth, say .020" or .030"? Try some of the #68 style SWCs which load to an OAL of about 1.250" and won't hit the feed ramp so hard.

I have only seen setback in factory loads that have been run in and out of the chamber a number of times, as in unloading and reloading with JHPs before and after practice with reloads. A little movement should get that round demoted to practice. If it sets back a lot it should be trashed.

My FLG is very concerned over this and loads his own defense ammo with a cannelure under the base of the bullet to keep it from setting back. He used to use one of the roll tools, slow as it is. Now he uses a tool that I designed and he built which cannelures the brass in one stroke on the loading press. Those bullets do not set back. He shoots the top round for practice when the hollowpoint looks battered.

 

[KLN]

Experience being a fairly reliable teacher, WP and I generally agree, and if it appears we do not, it is usually semantics. Probably that is the case here, but this is an important subject, and should be clarified.

I too have had factory pistol ammo set back in the case. I just don't use that kind of ammo any more. It should not happen, and in a high pressure cartridge, it can be catastrophic. I have a frightening looking .38 Super case on my bench as a reminder of that fact.

In rifles, the technique generally does not apply, except in highly specialized bench rest ammunition beyond the scope of this discussion.

In pistol reloads, I have never experienced bullet set-back, under any conditions, after properly sizing my expander plugs. Obviously, it could theoretically happen, with enough force, but it would be a pretty unusual set of circumstances.

If auto pistol reloads can have the bullet set back into the case when pushed hard, nose down on the bench by hand, there is a problem which must be addressed. It is caused by an expander that is too fat, and it cannot be solved by anything but a smaller expander. No amount of crimping or any other solution (including glue) will solve loose case tension on the bullet. You can fix it yourself, by the method mentioned above (which has been recommended by "experts" since the expander plug was invented), or you can have someone else do it, or you can buy a new, smaller diameter expander.

Spinning the expander on sandpaper is not a complex task, and it would be difficult to ruin anything. If you did, a new expander plug is not a large investment. If you are not comfortable with doing the job, you can always buy a new expander plug. Die companies have them available in different diameters just for this situation.

While my .38 Super contained the load mentioned above, it should not have been expected to. That experience reinforced the potential havoc that can be created by a too large expander plug.

 

[Sammy Fan]

The reason I set the OAL to 1.210 in is because I was advised to leave approx. 0.010-0.015 in. of bullet above the case mouth. I tried different OALs before when I tried to solve FTF problems but at that time did not notice any setbacks. I would try the longer OALs again, say 1.240-1.250 in. and see if it gets better.

 

[Hobbes]

Originally posted by Sammy Fan:
...and factory crimp to .460 in.
Is this enough crimp?

That is an extremely heavy crimp! Is that a typo? Read RMark's post. Take care.



[This message has been edited by Hobbes (edited 11-20-2001).]

 

[DBR]

Originally posted by Sammy Fan:
My 45 bullets would set back .into the cases 015-.020 in. after chambering. This happens to both 200 gr. LSWCs and JSWCs.
I set the OAL for lead to 1.210 in. and jacketed to 1.180 in. and factory crimp to .460 in.
Is this enough crimp? Is the decrease in OAL normal and how does it affect the firing of the round?

My manuals call for a .473 taper crimp on 45ACP. If you over crimp on lead bullets, the lead will take a set and the brass will spring back resulting in less holding of the bullet. You should check a reloading manual for yourself, it seems like you are over crimping.

 

[45shortcolt]

Use a Lee seat/crimp die from a regular die set. It's a cross between a taper/roll crimp and does quite a nice job. No problem with setback whatsoever and it slips over the feedramp into the chamber nicely.

 

[Sammy Fan]

The crimp got to .460 over a period of time when I was trying to solve this problem of cartridge FTF by nose diving into the ramp.
I have since polished and contoured the ramp so now feeding is OK, but the 1st round of a full mag would still take a severe nose down attitude towards the ramp but would be deflected up to chamber. Since the round is still impacting the ramp at an awkward angle, the bullet still takes a set of approx. 0.020 in.
I have noticed the permanent set of the bullet by the crimping
action as well. I probably should start over.
The cartridge takes a path of hitting the ramp at such an angle first , then sharply changes direction to hit the top of the chamber before changing direction again to fully chamber. Is this zig-zag route really the normal course for the top rounds?

 

[DBR]

You might also have a magazine problem. LSWC profile bullets do not feed like hardball and some magazine feed lip designs can cause the "nose dive" you describe.

 

[tmg]

Great thread, I have the same problems with some of the reloads I have been getting 200gn rnfmj, that's part of the reason I decided to start reloading myself, besides it will save a ton of money and I'll learn more about the hobby itself.....

Originally posted by Sammy Fan:
My 45 bullets would set back .into the cases 015-.020 in. after chambering. This happens to both 200 gr. LSWCs and JSWCs.
I set the OAL for lead to 1.210 in. and jacketed to 1.180 in. and factory crimp to .460 in.
Is this enough crimp? Is the decrease in OAL normal and how does it affect the firing of the round?

 

[shooter452]

Use Dillon die sets, or at least the sizing die. I've loaded just about every bullet available, cast and jacketed, and every one of them is supported by smaller diameter brass behind the bullet. I've also never had any bullet set back, including a number I loaded years ago as test dummies. The bullets got so beat up I had to throw them away, but they didn't set back. It makes kind of an ugly round, with a bit of a wasp waisted look, but setback is NOT a problem.

In my experience, no crimp, taper or roll, affects setback at all. Initial tight bullet fit is the key.

 

[REDDAWN]

SAMMY FAN: YOUR OAL should be 1.245-1.250 your crimp should be between .469 to .471 GOOD LUCK (200 LSWC)