5.56 rounds are pushed into case further than others

[DungBeetle]

This is kind of hard to explain, but I bought some Winchester lake city 5.56, and a few of the rounds, the bullet is pushed into the case a little further than the rest. Most of the rounds, those grooves (cannelure) around the bullet sit just above the neck, while a few of them, those horizontal lines are pushed just below the neck where you cannot see them. Are these safe to fire? It is brand new ammo. Thanks!

[Recycled bullet]

Hey dung beetle what a name!! Take some pictures so that we can see them and measure it with your caliper and share with that measurement is!!

I want to say the rule of thumbnail is that if the overall length difference is less than the thickness of your thumbnail and if it's a starting load and not a maximum load you're probably not going to blow your gun up.

However if some of the casings are telescoping when chambered where the bullets are getting jammed into the brass and the overall length varies by a quarter inch do not use that that is dangerous!!

The low quality of factory ammo is an excellent reason to get into hand loading.

[gwpercle]

If you reload ... take your kimetic bullet puller and gently tap the deep seated rounds back out , don't pull the bullet completely out the case ... just move it out to match the other rounds .
If you pull the bullet too far out ... simply re-seat them to desired location with seating die .
Easy fix if you are a reloader .
Gary

[Rimfire5]

From my experience, a change of OAL of 0.002 changes the muzzle velocity by 1 fps and if the change in length is shorter, the velocity increases.

If the bullets lengths are getting shorter by 20 thousandths (and to me that would be a lot), you still will have an mv increase of only 10 fps.
If you measure factory ammo that is all the same OAL with a chronograph, you will find extreme velocity changes that are sometimes 3 to 4 times that.
Primer to powder ignition can vary that much in the extreme.

I wouldn't be worried about a minor change in bullet length until I started to see high pressure signs in the brass.

[Shadow9mm]

Could just be variances in the bullets, possibly case length. I would say most likely fine and normal. Do you have calipers to measure the loaded round lengths? Ideally you would want to use a bullet comparitor to measure off a point on the ogive, but measuring length will tell you a lot more than the relative position of the cases mouth to cannelure.

[44 AMP]

Ideally you would want to use a bullet comparitor to measure off a point on the ogive, but measuring length will tell you a lot more than the relative position of the cases mouth to cannelure.

I don't see where a comparator will tell you anything useful. You can already see that the bullets are seated to different depths. A caliper will tell you if the overall loaded length is different (and how much).

Possible some bullets got seated slightly deeper, the COAL will tell you. Possible some of the cases are longer so the same COAL results in the bullet being seated slightly deeper in the case.

Generally speaking crimping where there is no place to crimp into can be a problem, and in the worst case, can buckle the case, even to the point where it will not chamber. In your case, the cannelure is just a bit too deep but likely won't be an issue if the rounds chamber properly.

[DungBeetle]

Hey! Thank you for the reply(s). Unfortunately my camera will not focus close enough to show what I am talking about. And I do not have a caliper (I know I know) yet. If I shine a light at the round, I can barely see those lines on the neck while most of the rounds, those lines sit flush or just above the neck. It is factory new Winchester M193 from lake city so I imagine it has to be okay and within spec? I am just OCD when I noticed the slight difference.

[Jim Watson]

Compare the cannelure locations.
Might just be cheap army reject bullets with irregular groove location.

[rg1]

My experience with M193 military bullets over many years of loading shows a lot of difference in tip shapes. Some have a more sharply pointed tip while others are a little blunter. Also the bullet cannelures of these M193 are placed measuring from the tip. This makes the cannelures higher from the base with a sharp tip and lower on the bullet with a.blunt shorter top. Seems commercial bullets the cannelures are placed measuring from the base making the cannelures more consistent on seated bullets. Measure from the tips and you’ll see they are probably the same distance from the tip. Since they are seated using the ogive the bullets are seated into the case the same, only the cannelures are varying.

[Metal god]

If you’re using your phone for the photos . Take a picture at whatever distance it focuses on then zoom in and crop , should work just fine .

Like 44 says just checking the cartridge overall length will tell you where the variances are if the overall length varies from round round I’d have some concerns . Not so much safety, but just who the heck loaded these so poorly.

If the cartridge overall lengths are all pretty much the same than the variances in either the crimp groove or the case length . Which again I would not be too concerned about, but would wonder who the hell prepped these components?

I bought some cheap 223 bullets at the gun show once I think I still have some . The crimp groove was incredibly inconsistent and would look as you describe when loaded.

[Shadow9mm]

44AMP
Are they seated to different depths? Based on my experience I do not feel that using the amount of cannelure showing above the neck is a valid way to determine that.

Bullet seaters contact a portion or point on the ogive not the point of the bullet itself. Thus measuring with a comparitor, which does the same, will give you a much better idea of the consistency of the seating depth than measuring off the point. This is why I recommended it as an alternative to COAL.

Having loaded a fair bit of 55g fmj in my m193 clone loads, I have found that there is generally a fair bit of visual variance in how much cannelure is showing. This is even with cases trimmed to the same length, as well as bullets seated consistently to within +/-0.001 when measured with a comparitor. I can do better with better bullets, 55g fmj do not have the most consistent shape as rg1 noted. I have also noted variances in cannelure placement and width from lot to lot.

So to answer the question the ammo needs to be measured, the rest is just speculation.

[Metal god]

I have found that there is generally a fair bit of visual variance in how much cannelure is showing. This is even with cases trimmed to the same length, as well as bullets seated consistently to within +/-0.001 when measured with a comparitor. I can do better with better bullets, 55g fmj do not have the most consistent shape as rg1 noted. I have also noted variances in cannelure placement and width from lot to lo

When loading 55 grain projectiles I load almost exclusively Hornady 55gr fmjbt and trim my cases every time . My bullet cannelure is very consistent to my case mouth . I got the impression from the OP that there’s a significant difference from bullet to bullet or round to round which I think COAL would show if the problem was seating depth. I do agree a comparator measurement would be a more consistent and precise measurement to work from .

[44 AMP]

Bullet seaters contact a portion or point on the ogive not the point of the bullet itself. Thus measuring with a comparitor, which does the same, will give you a much better idea of the consistency of the seating depth than measuring off the point.

Ok, the comparator contacts a point on the ogive, in the same manner the bullet seating stem does, but is it the same point? The comparator is dependent on consistent ogive at the point of contact, bullet to bullet, so, a bullet that is slightly "fatter" or "thinner" at that contact point is going to give you what kind of reading??

My point about measuring over all loaded length is for comparison between the cannelure showing and cannelure hidden ammo the OP has. One must first discover a difference, before you can decide if it is significant, or not.

IF, for example, the rounds with the cannelure covered are .0Xx shorter than the other "normal" rounds, that is something you need to know before you can figure out why.

Sure, there are lots of possibilities, inconsistent bullets, or seating depths, or case lengths, or possibly things we haven't thought of yet.

It LOOKS like slightly deeper seating depth hiding the cannelure under the case mouth, but, is it?? Or something else that produces the same visual effect?

Bullets with slightly different locations of the cannelure (across the same lot) can produce that effect and still have the same over all loaded length.

Another possibility is that the hidden cannelure rounds have cases with poor neck tension which allowed the bullet to move slightly deeper into the neck than the other rounds.

Also consider that GI ammo is loaded "good enough to work" not "best possible ammo", and this might simply be an example of a bit more slop than usual.

[Unclenick]

Over the years I have encountered some odd errors in commercial ammo. I once had an LC 30-06 case that weighed about 35 grains more than it's brethren from the same lot. Shining a light down in revealed a dark mass on one side of the web that turned out to be a flattened blob of lead that probably fell in from the bullet placing gear. You may have got bullets off a seating tool that had a similar lump get caught in it, or it simply may have got loose or otherwise out of adjustment.

If you want, you can pull the bullets to compare to others to be sure they match, then reseat them.

[Metal god]

My point about measuring over all loaded length is for comparison between the cannelure showing and cannelure hidden ammo the OP has. One must first discover a difference, before you can decide if it is significant, or not.

A comparator has always I can’t emphasize this enough, will always give me a more consistent measurement than off of any tip of any bullet . This will tell you how consistent your bullet is seated . I’ve done limited test with 77 grain Sierra match kings among several others but the SMK seem to be particularly bad in this regard .. With a tip to base of bullet variance being as much as .011 While the same bullets using a competitor are just over .001 variance. My point there is. Measuring cartridge overall length is likely going to give you a less consistent measurement than how consistent the bullet is actually seated.

As to the seating die stem and the comparator meeting the bullet in the same place . I’d have to say almost guaranteed not to match up . Again comparing my seating, dies and comparators plural because I have Sinclair and Hornady comparators. The Sinclair measures significantly closer to the actual diameter of the bullet then the Hornady does. Likewise, with all my seating dies. None of them contact the bullet in the exact same place , close but never the same. That’s generally irrelevant as long as you use the same die throughout the same batch or for the same specific load they should be relatively consistent.

Here is an example of seating stem ( top ) and both comparator marks below .

[gwpercle]

Originally Posted by DungBeetle

This is kind of hard to explain, but I bought some Winchester lake city 5.56, and a few of the rounds, the bullet is pushed into the case a little further than the rest. Most of the rounds, those grooves (cannelure) around the bullet sit just above the neck, while a few of them, those horizontal lines are pushed just below the neck where you cannot see them. Are these safe to fire? It is brand new ammo. Thanks!

It sounds like the ammo you have bought may be ... Factory Seconds ... or Rejects .
If so you realy shouldn't shoot them ... they were inspected and found not to comply with factory specifications . Break them down for reloading components .
It may cost more but good ammo pays for itself in the long run .
Gary

[Shadow9mm]

Originally Posted by gwpercle

It sounds like the ammo you have bought may be ... Factory Seconds ... or Rejects .
If so you realy shouldn't shoot them ... they were inspected and found not to comply with factory specifications . Break them down for reloading components .
It may cost more but good ammo pays for itself in the long run .
Gary

Not necessarily. You have to consider the reason they were "rejected". It is not necessarily because of safety concerns. You have to consider if this was produced for the public or for a contract. Specification for a contract could be failed but perfectly within the factories specifications for commercial production. And the specifications for either could be ES/SD, average velocity, bullet weight tolerances, or any other reasons, not just safety.

[tangolima]

Originally Posted by Shadow9mm

Not necessarily. You have to consider the reason they were "rejected". It is not necessarily because of safety concerns. You have to consider if this was produced for the public or for a contract. Specification for a contract could be failed but perfectly within the factories specifications for commercial production. And the specifications for either could be ES/SD, average velocity, bullet weight tolerances, or any other reasons, not just safety.

I doubt they will sell the rejects deemed unsafe. They will be sued six ways to sunset.

-TL

Sent from my SM-N960U using Tapatalk

[44 AMP]

Unsafe, and rejected as not meeting mil spec contract requirements in all areas are different things. Obviously unsafe fails to meet spec, but lots and lots of things can fail to meet spec and still be perfectly safe to use.

[ballardw]

You can fail to meet Mil spec by using the wrong font on boxes sometimes (if the font size or face was specified in the specification for example).

You might not believe the things that get specified. Ever read a 3-page specification for plastic coaches whistle?

[Unclenick]

One thing I did with a gnarly lot of military surplus 7.62 NATOs about thirty years back, was get one of the Hornady cam-lock pullers and just pulled them all down. I dumped all the powder into a bin and weighed it and divided by it by the number of pulled rounds to be able to recharge the cases later from that info. I then used a neck sizing die To reduce the neck and crimp, followed by a mandrel in a Sinclair mandrel die body to expand it, then recharged the cases and reseated the bullets. My powder dispensing was a good deal tighter than the original (1.8-grain span of stick powder, originally). The bullets were nothing to write home about, so it didn't actually shoot any better, after all that, so I stopped the reloading after fifty rounds of scattergun groups and subbed some SMKs, and those shot targets scores just fine. So I started with sloppy loads and funky bullets and wound up with something like 400 finished rounds of "Mexican Match."