RTFM: If the rifle manufacturer says X grain ammo, pay attention (pics)

[techres]

Rifle is .223 1/12 twist bolt action and manual says 55 grain ammo only. 

Someone advised shooter that 62 grain is a better choice for KD and the shooter got some.  It was immediately obvious that he had a problem:



Two groups were of one brand and the third was of a different brand.  However as soon as we went back to 55 grain ammo, it grouped as happy as could could be.

Lessons learned:

His rifle shot fine until he tried to follow advice.
Keep backup ammo on hand.
Last minute changes are bad.

Oh, yeah,

Don't forget to read the manuaal

[SSG Platz]

1-12 twist cannot stablize the larger grain bullets, they were tumbling at 25, that's why the holes look the way they do, the rounds hit the paper sideways. Didn't know if you noticed that so I though I would mention it.

~PlatzOut~

[techres]

Yeah, we knew the rules but tried to sneak past old newton and his darn physics anyways.   

Note two things:

1. It is extremely consistent in the keyholing - every round tumbled.

2. The shooter still managed 6-7 moa groups.  Makes me want to try an entire AQT ballistically unsound just to see if I could score and get me a rocker that reads "keyholer".

[SPQR]

1-12 twist cannot stablize the larger grain bullets, they were tumbling at 25, that's why the holes look the way they do, the rounds hit the paper sideways. Didn't know if you noticed that so I though I would mention it.

~PlatzOut~

Now I wish the internet had tone of voice icons because if Platz said this in the Mr. Obvious voice from the Bob and Tom show that would be hilarious.



When I was asked what kind of ammo he should shoot I didn't know what rifle was being used.  Since he asked about 5.56 I suggested 62gr. because it is what can be found in bulk.  Turned out he was shooting a varminter with a 1-12 twist.  The interesting thing for me is that it shows how good of a shooter Bryce is.  In a south facing west wind range he still shot that good without ballistic behavior.  He might as well have thrown them down there. 

That was a fun morning. 

[TaosGlock]

Great resource! Thanks for posting that!
TG

[Nero]

New Title:  How to simulate a musket using a modern rifle.   

[Johnnyappleseed]

A Camp Perry shooter told me that an M14 is designed for shooting a 150 grn bullet;
He said shooting a 180 grn will damage the operating rod.

Can anyone confirm this info ?

[SSG Platz]

It's not so much the grain of the bullet, it's how hot the cartage is, if you shoot loads that are too hot it could break you're rifle, now some one correct me if I'm wrong, but from what I understand is if you have one that has been made 2008 or later you can shoot whatever you want though it, the ones before then are sensitive to internal pressures.

~PlatzOut~

[Nero]

A Camp Perry shooter told me that an M14 is designed for shooting a 150 grn bullet;
He said shooting a 180 grn will damage the operating rod.

Can anyone confirm this info ?

I've read that it's a possibility, due to higher gas pressures developed.  That said, I ran a couple of boxes of Federal 180s through my M1A when I first got it, as part of ammo tests, with no noticeable problems - other than the fact it didn't like them.  Mine's a National Match, which are said to like heavier bullets, and sure enough mine's happiest with Sierra or Nosler 168s, but 180 was too much.  I understand that 'vanilla' M1A/M14s are set up for the 147gr NATO load, and tend to like something around there or 150gr.  As always, YMMV, each rifle has its own personality.

[SSG Platz]

2. The shooter still managed 6-7 moa groups.  Makes me want to try an entire AQT ballistically unsound just to see if I could score and get me a rocker that reads "keyholer".

You can get away with that at 25, but much further out you are going to have have problems just staying on the paper.

~PlatzOut~

[asminuteman]

New Title:  How to simulate a musket using a modern rifle.   

I heard that tim! 

besides the holes are quite tiny.......   .62 cal 300gr rb makes much large holes then that! 

gezzz .223 69gr is just bird shot

[LayloPro]

hmmmm, 62 grain birdshot....ever think about that in the world of smoothbores?? You could probably put about a dozen of them in a charge.....

I've heard some stories about op rod damage in 14's, and can only say that the only op rod I saw damaged was when the fellow tried using it for a pry bar....

Some of these guys who "collect" (but never seem to shoot) their rifles have some fabulous tales about the finickiness of their safe queens....what ever....

Find out what your rifle is most consistent, and accurate with, and go with that......

Free bore is important too, for those who reload......

BTW, that is truly a poster child for showing real keyholes to folks......picture perfect!!!

As always, YMMV....

LLP

[wcmartin1]

A Camp Perry shooter told me that an M14 is designed for shooting a 150 grn bullet;
He said shooting a 180 grn will damage the operating rod.

Can anyone confirm this info ?

It's the gas port pressure that will get you. 

Download and read the attachment here - http://appleseedinfo.org/smf/index.php?topic=277.msg5896#msg5896

[wcmartin1]

Handy .223 barrel twist chart for you reloaders based on bullet length (the heavier bullets are longer... duh  ) -

http://le.atk.com/pdf/223_MinimumTwistRates.pdf

[AFTERMATH]

According to a lot of 'know-it-all' folks I've encountered at gunshows, etc.; 5.56 was designed to fly sideways and tumbling.  That's why it's so effective.

[Nero]

According to a lot of 'know-it-all' folks I've encountered at gunshows, etc.; 5.56 was designed to fly sideways and tumbling.  That's why it's so effective.

I think that was supposed to happen after impacting the target.      

[hinermad]

According to a lot of 'know-it-all' folks I've encountered at gunshows, etc.; 5.56 was designed to fly sideways and tumbling.  That's why it's so effective.

I believe it was supposed to tumble after it entered a living target, using its kinetic energy to damage tissue and bone rather than just punch an exit wound and keep going.

Dave

[mj52]

What did that sound like?

It looks like a Regetta without any rules

I'm surprised they shot 15 rounds

[techres]

I'm surprised they shot 15 rounds

It sounded normal, and they shot 15 rounds because we tried different brands to be sure of the effect.  We doing "science"...

[Nero]

I'm surprised they shot 15 rounds

It sounded normal, and they shot 15 rounds because we tried different brands to be sure of the effect.  We doing "science"...

Myth busted!

It looks like a Regetta without any rules

Yeah, it sort of looks like one of those diagrams of Revolutionary era naval battles.  Just draw some little sails on there.

[SSG Platz]

I believe it was supposed to tumble after it entered a living target, using its kinetic energy to damage tissue and bone rather than just punch an exit wound and keep going.
Dave

Correct, that's why it can go in your chest and come out your butt cheek. Crazy how that stuff works.
If it tumbled the whole way you wouldent be able to hit anything further than say 50 yards with any kind of accuracy, unless your shooting at a barn.

~PlatzOut~

[techres]

Yeah, it sort of looks like one of those diagrams of Revolutionary era naval battles.  Just draw some little sails on there.

There's no crossing of any T in that pile, so it looks more like the battle off Salamis.  Or an infighting mess or corn candy on halloween.

Correct, that's why it can go in your chest and come out your butt cheek. Crazy how that stuff works.
If it tumbled the whole way you wouldent be able to hit anything further than say 50 yards with any kind of accuracy, unless your shooting at a barn.

~PlatzOut~

Yeah, tumble, yaw, wow.  The mouse round does roar.

[AFTERMATH]

According to a lot of 'know-it-all' folks I've encountered at gunshows, etc.; 5.56 was designed to fly sideways and tumbling.  That's why it's so effective.

I believe it was supposed to tumble after it entered a living target, using its kinetic energy to damage tissue and bone rather than just punch an exit wound and keep going.

Dave

That's what I tried to tell them...    But what can a Senior Instructor tell a former sniper? 

[stoneknives]

Pretty fair groups considering the rounds were going sideways.

[Sly223]

Best key hole representation I have ever seen thanks for the Science!

[SSG Platz]

It will be at 25, once you get further out you won't even be on paper let alone the target backer.

~PlatzOut~

Pretty fair groups considering the rounds were going sideways.

[SPQR]

It was at 25.  At 100 they were almost staying on on an 11x17 piece of paper and were still somewhat distinguishable as groups.  The holes weren't as clean so we didn't get that "You sank my BATTLESHIP" feel.

[Charles McKinley]

Your can buy bulk Federal in 55 grain.

[techres]

Well, I did manage to pull off one at 400 yards - from an SKS on KD day:



But that was a different rifle, ammo, and story all together.

[SPQR]

Its not that long of a story.  At 300 yards with a grimey SKS you were shooting 2 MOA with the top of your post even with the top of the backer.  At 400 yards you were splashing 25 yards shy of the backer and keyholing.  Of course, the parts of the story that are in between are fun.