Crimp plus neck tension vs neck tension alone?

[Tuckerp229]

http://www.rifleshootermag.com/ammun...ds/index1.html


A good article on reloading. This supports my findings which at first baffled me, namely that some crimp in addition to neck tension will often improve downrange bullet performance as opposed to running with neck tension alone. For those that own and shoot rifles with magazines, this is not an issue since the crimp holds things in place during recoil, loading and unloading. For single cartridge rifles or competitive shooting where rounds are singly loaded, this really goes against the grain of prevailing belief. All I can say is experiment a bit with neck tension and crimp. You have nothing to lose but average group spread.

To go right to the crimping section in the article scroll down to the lower quarter of the first page.

[Tim R]

Problem is Tucker I'm not disturbing the jacket on a match bullet with a crimp.

[Tuckerp229]

Good point. I wonder how much jacket disturbance it would take to affect the downrange performance? The article says nothing about about of crimp. I have used Nosler Accutips and Sierra Matchkings in some of my tests. My tests start with no crimp and then progress by increments of 5 ftlbs. of crimp force until the Lee FCD die collets close. Often- not always, the 5 or 10 Ftlb increments show an improvement in downrange performance over no crimp. Sometimes the improvement comes with higher crimp forces...say 20-30 Ftlbs.

My question at the moment is that at the low crimp forces the crimp force is so subtle that I am wondering whether the jacket is disturbed very much or at all. Still the improvement is in these instances very real. I think I will run another batch, range test while holding back an example of each crimp force increment and then pull the bullet on the best ones so I can inspect the bullet jacket.

My next question will be whether an improvement at 100 yards automatically yields improvement at 200,300 yards or if at some distance the potential of jacket disturbance takes over and affects the bullet performance negatively?

[Brian Pfleuger]

The idea that crimping helps with accuracy is not based so much on the crimp itself but on the fact that it increases the start pressures before the bullet moves and can help with more consistent powder burn in some cases.

More consistent powder burn "creates" more accuracy than the potential damage to the bullet destroys. Particularly since the crimp should not be causing any damage to the bullet anyway. No one says you've got to crimp so much that you create a cannelure in the bullet. Just tightening down the mouth is sufficient.

[4runnerman]

Hello Tucker. My 2 cents worth

I loaded 100 223's,Savage FVSS. 50 cases i crimped lightly,50 cases neck tension only. Shot in groups of five,cleaning bore every five shots. FPS increased with crimped rounds,but accuracy did not. I did not mess with different crimp tensions as you are talking about though. All rounds loaded same COL, same powder charge,same primer. I am intrested in your findings when you get them. As maybe i need to look a this again also. Keep us posted.

[Brian Pfleuger]

Cleaning the bore every five rounds likely introduced an additional variable that would hide any effect from crimping. All my guns take at least 3 rounds to "settle" after a cleaning.

[4runnerman]

Hello Peet.. It was something i considered,but it made no diffrerence on my uncrimped rounds. So i had to throw it out as a possability. I hope OP keeps this post going as i would love to find out what he discovers. I might go back to the drawing board for my pet load again.

I am not sure how much more accuracy i can expect to get from this rifle as it is unreal right now,But i will take any more i can get.

[Tuckerp229]

Cleaning the bore every five rounds likely introduced an additional variable that would hide any effect from crimping. All my guns take at least 3 rounds to "settle" after a cleaning.

A completely different subject but I just received my april Issue of "Guns" of gunsmagazine.com. They have an article in this issue titled "Stop the Madness". This is the second article in a year that have seen debunking the whole concept of barrel cleaning and break in. The other artice was in the NRA Rifleman. They came right out and said that the reason some of the barrel companies have a break in/cleaning procedure was to get the customers off the phone! As I said a whole 'nother subject, but talk about starting a fire storm.

As for my experiments, I am willing but the weather up here in the North is still a bit frightful. We do have a warm up but it may be several weeks before I can do the range testing.

[4runnerman]

As for my experiments, I am willing but the weather up here in the North is still a bit frightful. We do have a warm up but it may be several weeks before I can do the range testing

Im with ya Tucker,. I went out last weekend,could not get with in 1/2 mile of our range. Im starting to get with drawl symptoms

[snuffy]

By Wayne van Zwoll

When you consider that time is money, factory-loaded ammo is less expensive than what you can load yourself. And the stuff you buy at the store was loaded by companies with modern machinery and decades of experience, so, yes, it's probably superior to what you could load at home.

However, because many shooters tend to be self-reliant--with a preference to roll their own--handloading remains a passion among those who will look at a given load and wonder what if. . .

This guys opening statement in this article brings up a question as to his expertise in general. He seems to be trying to talk about reloading basics, then goes into some detailed advanced procedures.

If time is money, how am I missing out? Who's failing to pay me for my leisure time? Then the statement that factory ammo is accurate enough, why bother handloading. I can out-do any factory ammo I have tried in any of my weapons. And my free time is just that, free. I only make wages when I go to work.

His whole article is a mixture of half-truths and myth. Primers can not be contaminated by skin oil. Most lubricating oils will not contaminate them.

I don't crimp ANY of my rifle ammo. Not even my .223 when loading bullets with a cannelure. Or my M-1 garand. Neck tension alone will hold any bullet just fine, IF you know how to set-up a sizer die.

The exception to that is the lee collet neck sizer. They usually have much less neck tension than needed. Reducing the mandrel outside diameter is easily done with a drill and some fine Emory cloth.

[F. Guffey]

Snuffy, Why the nickel to adjust the die off the shell holder? My opinion, install a case in the shell holder, raise the ram, then adjust the die down to the case, when the die contacts the mouth of the case back the die off (I do not care how much!) 1/2 turn? ( .0355 thousands) to prevent the die from crimping, then start adjusting the seating depth of the bullet,

Different version: I make transfers, that would be a case with a seated bullet and the flash hole/primer pocket drilled out to a diameter that will accommodate a cleaning rod. When seating a bullet the reloader should know the length of the chamber from the face of the bolt to the rifling, to determine the maximum OAL length of the chamber remove the bolt, chamber the transfer, push the bullet out to the lands, when the bullet stops (quit pushing) remove the transfer, install it in the shell holder and before screwing the die down loosen the stem to the seater plug and raise it to prevent contact with the bullet. After raising the seater plug screw the seater die down until it contacts the case mouth, right there the die is adjusted to crimp if all the cases are the same length, if a crimp is desired secure the lock nut on the die to the press, THEN, adjust the seater plug down until it contacts the bullet, STOP, then secure the nut to the seater stem, and now the reloader is seating and crimping, and crimping is no more than a breath of effort.

Seating without crimping: Same thing with one exception, before securing the seater die to the press back it off (I do not care how much) 1/2 turn or .0355 thousands then secure the lock nut on the die to the press, then adjust the seater plug down to the bullet for seating the bullet off the lands .000, if the reloader chooses to seat the bullet off the lands like me because I am a big fan of the running start I use a height gage on the seater stem, when adjusted down to the bullet the stem is at .000 off the lands,, I zero my gage then adjust the seater stem down for seating bullets for OAL AND off the lands. Without additional tools.

Foot note* To seat a bullet with a transfer the reloader must know the test case was made without the bolt, so head space is not considered, but a reloader should be able to determine head space in thousands, after all the reloader is a reloader. Point being maximum OAL for the chamber and at the lands does not include head space, for me? Not a problem, again, I am the fan of the running start. some say 'jump', I say bullet hold, they say neck tension.

An opinion, the nickel is another bad habit, 6 steps to reloading?

F. Guffey

[snuffy]

Snuffy, Why the nickel to adjust the die off the shell holder? My opinion, install a case in the shell holder, raise the ram, then adjust the die down to the case, when the die contacts the mouth of the case back the die off (I do not care how much!) 1/2 turn? ( .0355 thousands) to prevent the die from crimping, then start adjusting the seating depth of the bullet,

HUH?!!! Are you attributing ME with the use of a nickle? That's from the article by Von Zwoll!

Bullet Seating
Install the seating die so there's at least the thickness of a nickel between it and the shell holder at the top of the ram's stroke. For the first cartridge, adjust the seating stem so the bullet is seated firmly in the neck but more shallowly than you intend for the final product. Fine-tune seating depth with that cartridge, pushing the bullet into the case in short increments until it's right.

Your posts are not read by me. You are always touting some home made gadget that apparently satisfies your need to tinker. Impossible to follow your stuff.

[F. Guffey]

Snuffy, I never know how indignant someone can be until I give them a chance, I started with "Snuffy, Why the nickel to adjust the die off the shell holder? My opinion"
and ended with "An opinion, the nickel is another bad habit, 6 steps to (omitted 'great) reloading?" then you thought I accused you of recommending the use of the nickel then you finished with " Impossible to follow your stuff"

The link posted by Tuckerp229 has a title, 6 steps to great reloading, I did not accuse you of anything, I did notice you did not say anything good about the article and did not offer suggestions in a constructive manner. Complaining is BITC#IN&, Complaining without offering a better way to do it in a constructive manner is also BITCH%&G.

Provoke someone to think? With that I say sometimes I only enjoy 50% success, I did not provoke you to think, I was only successful in provoking you, and that Sir was not my intent.

And for those that do not have deep pockets and can not stretch their money to include reloading equipment, yes sir, I am very proud of my effort.

F. Guffey

[Chinny33]

I crimp all of my rifle rounds.

I mainly use AR-15s, AR-10s, M1As, Mini-14s, and a Steyr Aug. Im a semi-auto nut. I can clearly tell that when any semi auto chambers a round it is pretty harsh on the bullet. not all feed ramps are perfectly polished and thus can shake up cartridges. IMHO I think that a slight crimp can maintain the integrity of the seated bullet.

I have yet to notice a difference in accuracy with a crimped bullet. The crimps I put on my cases are VERY slight. I have ran experiments in most of my rifles and have seen changes in seating depth before and after chambering them manually, trying to cycle rounds as if they were being fired normally by the bolt. Some bullets shifted deeper and some shifted farther out.

My other experiences after crimping was wondering if i have altered the conical integrity of the bullet after crimping. I used calipers and noticed zero changes in the shape or circumference in the bullets after I lightly crimped the cases. Some bullets I use do not have a crimping cannelure on them.

If I saw clear evidence that crimping bullets degrades accuracy @ 100 yards, I'll be the first to stop crimping bullets.

I have read that benchrest shooters say NO to crimping, because it degrades accuracy, but I have yet to read proof or statistical evidence that it does.

Right now I am torn. I have not personally tested loads to see if crimping changed my velocity or my accuracy. Honestly, I dont have the range time to do that. The nearest rifle range to my house is 55 miles away.

Does anyone have personal experience with evidence suggesting that crimping, even light crimping can DEGRADE accuracy?

[Tuckerp229]

I mainly use AR-15s, AR-10s, M1As, Mini-14s, and a Steyr Aug. Im a semi-auto nut. I can clearly tell that when any semi auto chambers a round it is pretty harsh on the bullet. not all feed ramps are perfectly polished and thus can shake up cartridges. IMHO I think that a slight crimp can maintain the integrity of the seated bullet.

All of my testing shows that crimping-even a light crimp can improve downrange performance. The operative word is can. One must establish the right amount of crimp and secondly, repeat it. The benefit of crimping has been explained to me like this- when one crimps, they lock the bullet into the case and hold it there until a certain level of pressure has been built up within the case. Release of the bullet from the case is at a more consistent time and by a more consistent pressure. This is why SD will drop when using the right amount of crimp. See this link: http://www.ar15armory.com/forums/DAT...LS-t90707.html

I have yet to notice a difference in accuracy with a crimped bullet. The crimps I put on my cases are VERY slight. I have ran experiments in most of my rifles and have seen changes in seating depth before and after chambering them manually, trying to cycle rounds as if they were being fired normally by the bolt. Some bullets shifted deeper and some shifted farther out.

This surprises me. My testing and indeed many others have discovered that the right amount of crimp really tightens things up downrange. Certainly the bullet depth or OAL is another key. I suffer from "Old man syndrome". This means that when deer hunting I am loading and unloading my rifle when I water the dog. My reloads OAL length be shot by mid-morning if I didn't crimp.

My other experiences after crimping was wondering if i have altered the conical integrity of the bullet after crimping. I used calipers and noticed zero changes in the shape or circumference in the bullets after I lightly crimped the cases. Some bullets I use do not have a crimping cannelure on them.

Enough crimp can alter the surface contour of the bullet. Since this has not been a negative in my testing my jury is still "out". For me I am now wondering how much change of the surface is needed and at what distance before the ballistics are changed? You might be interested to know that "creating a canelure" is listed as one of the benefitsof the Lee Factory Crimp die!

If I saw clear evidence that crimping bullets degrades accuracy @ 100 yards, I'll be the first to stop crimping bullets.

You can quit waiting. The right amount of crimp will do quite the opposite.

I have read that benchrest shooters say NO to crimping, because it degrades accuracy, but I have yet to read proof or statistical evidence that it does.

Old sacred creeds die hard. Again it is a mute point if you load multiple rounds in your weapon or must ever unload and reload the same cartridges.

Right now I am torn. I have not personally tested loads to see if crimping changed my velocity or my accuracy. Honestly, I dont have the range time to do that. The nearest rifle range to my house is 55 miles away.

Now here is the heart and pain of the whole problem...55 miles to the range? My God man how do you survive?

Ditto my previous on that last question.

Great points and questions Chinney33.

[4runnerman]

Quote:
I have read that benchrest shooters say NO to crimping, because it degrades accuracy, but I have yet to read proof or statistical evidence that it does.

I bench shoot and NO CRIMP for me. In fact the one person i shoot with that took second place this year also does not crimp(both bolt action).

Tucker--You were doing some tests on this right?. What were your findings?.

[Bamashooter]

I dont crimp for bolt action or single shot. I do lightly crimp for my semi auto rifles. I get pretty good groups with crimped ammo. My handloads are more accurate than any factory ammo I have ever used so I dont really care if it degrades accuracy, becouse they are pretty accurate with the crimp.That gives me piece of mind so any accuracy lost ( if any) is worth it.

[Tuckerp229]

Quote:
I have read that benchrest shooters say NO to crimping, because it degrades accuracy, but I have yet to read proof or statistical evidence that it does.

I bench shoot and NO CRIMP for me. In fact the one person i shoot with that took second place this year also does not crimp(both bolt action).

Tucker--You were doing some tests on this right?. What were your findings?.

About 85% of the time some amount of crimp performs better than zero crimp. This is both load recipe and weapon dependent.
It just so happens that every time I test for optimal crimp value, I leave part of the tray full of cartridges "back" with zero crimp. These cartridges are range tested along with the crimped cartridges.
As a side note optimal crimp force from zero-maximum is load and weapon specific.