.223 question about bullet length vs magazine.

[M. Sage]

I'm starting to learn exactly how much I don't know...

What is the longest bullet that can be safely loaded into a .223 case to an OAL that will fit and feed from an AR magazine? I've been splitting reloading costs with a friend of mine who just bought a LaRue PredatAR. Apparently the test target says it was shot using 75 grain ammo, so he's got it in his head that this rifle must like the stuff, and he's got to load that crap for it to "see what it can really do". Well, the bullets he bought are Hornady Match HPBT in 75 grain. My Lyman book doesn't have that exact bullet, but the OAL it suggests for other 75 grain bullets is 2.390. When I put calipers inside a PMag, I come up with a 2.250 max OAL to work in the magazine (which isn't exactly what it measured, but it's an educated guess at what would fit). Needless to say, I'm not exactly comfortable setting back the bullets .140 or more.

The bullets themselves measure around .985 (+/- about .010, some of which could be the calipers and me, but I'm still surprised at a match bullet having such a wide tolerance) long. Holding an unloaded bullet next to a case and looking at how far I'd have to seat the thing to fit a magazine, the base of the bullet winds up behind the shoulder.

For now, there's no way I'm going to try it. I just started loading .223 and I haven't even test-fired my first batch of "this will work!" 55 grain loads.

What do you say, oh interwebz?

 

[LJH]

Well it gets complicated; seating the bullet too far into the case can affect pressure, as well as accuracy. If you are not pushing the max loadings it will work, just not optimally.

 

[LJH]

But then again, perhaps not. Look at some of the 6.5 grendel loadings, 1/2 of the bullet is in the case past the neck and accuracy is outstanding.

 

[Vaquero]

Man! I gotta start hauling my load manuals with me. I loaded some magic bullets for a guy a looong time ago. He loved the accuracy and hated the oal. Nope, wouldn't fit his mag. Shit happens.

 

[TexMex247]

IIRC its 2.280" for most AR mags but, that probably varies a bit by body type, manufacture,etc. If you aren't loading to max or stuffing the bullet over a compressed load, the OAL really does not apply. You will always find loads listed at a MINIMUM C.O.L. for a MAXIMUM load. They are not listed by minimum lengths IME. However, intentionally loading bullets waay short even under low power loads might create a high pressure situation. In your case, you're ok to run shorter lengths as long as your're not at a maximum powder charge.

 

[M. Sage]

Definitely not going to jump into max powder charge. I loaded to about the dead center of the range the book gave me.

Thanks, I guess I'll try seating them deep and see how it goes. If it blows up his new LaRue, it was all his idea anyway.

 

[Dawico]

Maybe Larue shot them single shot with no magazine and a long OAL? Many people do that with heavy bullets pushed to high velocity (max or near max charges where pressure would spike if the bullets were set back to fit the magazine). Many rifles are more accurate with the bullet close to the lands. Very often this makes loading rounds a single shot proposition as the magazine is too short. This is not just an issue with ARs either.

 

[Dawico]

My general rule of thumb is to shake a round that I felt might be compressing a charge if I was loading under the recommended OAL. If I can hear the powder shaking the round is good to go (with medium charges and some common sense ofcourse).

 

[red1027]

I'm starting to learn exactly how much I don't know...

What is the longest bullet that can be safely loaded into a .223 case to an OAL that will fit and feed from an AR magazine? I've been splitting reloading costs with a friend of mine who just bought a LaRue PredatAR. Apparently the test target says it was shot using 75 grain ammo, so he's got it in his head that this rifle must like the stuff, and he's got to load that crap for it to "see what it can really do". Well, the bullets he bought are Hornady Match HPBT in 75 grain. My Lyman book doesn't have that exact bullet, but the OAL it suggests for other 75 grain bullets is 2.390. When I put calipers inside a PMag, I come up with a 2.250 max OAL to work in the magazine (which isn't exactly what it measured, but it's an educated guess at what would fit). Needless to say, I'm not exactly comfortable setting back the bullets .140 or more.

The bullets themselves measure around .985 (+/- about .010, some of which could be the calipers and me, but I'm still surprised at a match bullet having such a wide tolerance) long. Holding an unloaded bullet next to a case and looking at how far I'd have to seat the thing to fit a magazine, the base of the bullet winds up behind the shoulder.

For now, there's no way I'm going to try it. I just started loading .223 and I haven't even test-fired my first batch of "this will work!" 55 grain loads.

What do you say, oh interwebz?

I think the PMAG can hold a bullet longer than 2.250. I have not measured it myself so I could be wrong. I say this because the other day I was trying out some 50gr Blitz from Sierra, the Lyman manual says OAL to be at 2.235. They fit in the magazine but jam up the gun as they are too long. I went down to 2.225 OAL and they feed and eject. They were pretty accurate too.

Figuring out what YOUR gun likes adds to the reloading fun. Always watch for signs of over pressure.

 

[M. Sage]

I think the PMAG can hold a bullet longer than 2.250. I have not measured it myself so I could be wrong. I say this because the other day I was trying out some 50gr Blitz from Sierra, the Lyman manual says OAL to be at 2.235. They fit in the magazine but jam up the gun as they are too long. I went down to 2.225 OAL and they feed and eject. They were pretty accurate too.

Figuring out what YOUR gun likes adds to the reloading fun. Always watch for signs of over pressure.

I think you mixed some of the numbers up. 2.250>2.235.

 

[codygjohnson]

My longest loads, 77 grain SMKs, are 2.26" and feed from PMAGs. Most of my plinking/match stuff is 2.24-2.25".

 

[M. Sage]

My longest loads, 77 grain SMKs, are 2.26" and feed from PMAGs. Most of my plinking/match stuff is 2.24-2.25".

Thanks. I'll creep the length down until they fit and feed. Then we'll see how they shoot.

Eh, what do I care? They're not going in my rifle.

 

[skinman]

I do not know how the Hornaday 75 grain length compares with the Sierra 77 and 80 grain HPBT, but I found a Sierra document that shows the OAL as 2.260 for their 77 gr HPBT Match King and 2.550 OAL for their 80 gr HPBT Match King for use in a Colt AR-15/M2 HBAR.

I would suggest that you seat a bullet in an empty case and measure the chamber and find out what the max length is for that rifle and try a few soft loads using that data and play around with the charge until you find one that is accurate...That is what I did with my 30-06. If you are not sure how to do this, I can post instructions.

 

[dunnrite]

I think the PMAG can hold a bullet longer than 2.250. I have not measured it myself so I could be wrong. I say this because the other day I was trying out some 50gr Blitz from Sierra, the Lyman manual says OAL to be at 2.235. They fit in the magazine but jam up the gun as they are too long. I went down to 2.225 OAL and they feed and eject. They were pretty accurate too.

Figuring out what YOUR gun likes adds to the reloading fun. Always watch for signs of over pressure.

I think he was addressing you measuring the pmag, and would go into the mag but not chamber.

I load the same 75gr BTHP, and I load to Hornady's specs (2.250) and haven't run into any problems.

I run pmags also. They do just barely fit the mags, but there is still about 1/32". My Bushmaster seems to like them with 21.5 gr Varget

Hope it helps

 

[shortround]

I'm starting to learn exactly how much I don't know...

What is the longest bullet that can be safely loaded into a .223 case to an OAL that will fit and feed from an AR magazine? I've been splitting reloading costs with a friend of mine who just bought a LaRue PredatAR. Apparently the test target says it was shot using 75 grain ammo, so he's got it in his head that this rifle must like the stuff, and he's got to load that crap for it to "see what it can really do". Well, the bullets he bought are Hornady Match HPBT in 75 grain. My Lyman book doesn't have that exact bullet, but the OAL it suggests for other 75 grain bullets is 2.390. When I put calipers inside a PMag, I come up with a 2.250 max OAL to work in the magazine (which isn't exactly what it measured, but it's an educated guess at what would fit). Needless to say, I'm not exactly comfortable setting back the bullets .140 or more.

The bullets themselves measure around .985 (+/- about .010, some of which could be the calipers and me, but I'm still surprised at a match bullet having such a wide tolerance) long. Holding an unloaded bullet next to a case and looking at how far I'd have to seat the thing to fit a magazine, the base of the bullet winds up behind the shoulder.

For now, there's no way I'm going to try it. I just started loading .223 and I haven't even test-fired my first batch of "this will work!" 55 grain loads.

What do you say, oh interwebz?

According to the Hornady 7th Edition, for service rifle (AR-15) you can load a 75 grain bullet and seat it at 2.250 to 2.390, depending on the bullet.

Best to consult a reputable reloading manual than the "interwebz."

Lyman is a good general guide, but for every major bullet maker, there is a manual.

I.E. Hornady, Nosler, Speer.

 

[Texas Solo]

I would suggest that you seat a bullet in an empty case and measure the chamber and find out what the max length is for that rifle and try a few soft loads using that data and play around with the charge until you find one that is accurate.

^^^^^^^^^^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^^^^^^^^

My most accurate load ever was worked up by measuring my chamber, then subtracting .005" and loading to that length. Granted, it was a bolt action, but these loads still would not fit the blind magazine. They shot .250", but had to be single feed. This should give you some idea of just how much bullet "jump" exists in some rifles, and when limited to box magazine length, you'll be jumping even more.

Hornady Lock-N-Load Overall Length Gage Modified Case 223 Remington

Hornady Lock-N-Load Overall Length Gage Automatic/Lever Action

 

[Deavis]

When I put calipers inside a PMag, I come up with a 2.250 max OAL to work in the magazine (which isn't exactly what it measured, but it's an educated guess at what would fit). Needless to say, I'm not exactly comfortable setting back the bullets .140 or more.

If you look at the spec for 223 you will see that the maximum OAL is 2.260"

http://www.saami.org/PubResources/CC_Drawings/Rifle/223%20Remington.pdf

One would hope that magazines would accept a cartridge of at LEAST that length since that is the industry standard maximum. In the case of PMAGs, at least the 15 or so I own, that is the case. They will actually accept rounds that are longer than that length (+.030") but the best thing to do is simply test the round with the mags your friend plans to use. Load a few dummies, start long, and work down until the tightest magazine accepts them. Then feed them through the magazine by cycling the action to ensure they work. Then you'll have the max OAL you can load 75gr bullets to if you use those magazine if you choose not to use what Hornady recommends in their most recent manual.

The bullets themselves measure around .985 (+/- about .010, some of which could be the calipers and me, but I'm still surprised at a match bullet having such a wide tolerance) long

It is better to measure the consistency of a bullet from base to ogive rather than OAL but the OAL is usually much more consistent than that in my experience, +/- .002". To measure to the ogive, you need a bullet comparator.

 

[ROGER4314]

Any discussion of heavy .223 bullets must start with barrel twist rate. I re-read the thread and I don't see that listed anywhere.

Most of the match shooters who use heavy 70+ grain bullets single load them for the 600 yard matches. That works OK as the match is slowfire single load anyway.

At 600, the heaviest bullet I've fired is the 69 grain Match Kings in a 1:8 twist. The twist rate is all important. For those heavy bullets, you should probably have a 1:7 twist barrel. The other guys may disagree but that has been my experience on the 600 yard firing line.

A trick the tough guys use is to paint a bullet with magic marker and load it long until you get a mark from the rifling. Then seat the bullets below that dimensional length. That's as close to optimal as it gets but they may not load from the magazine.

Flash

 

[Dave W.]

My time has shown twist rate and bullet rate become important at distance. If a guy is shooting at 1-200 yards a slow twist rate AR can fire a heavy bullet and group just fine. Bullet OAL in an AR needs to be understood without regard to distance.

 

[OLDVET]

I routinely set my C.O.L. at 2.25" and the bullets operate fine in my Pmags. Where you run into trouble is with larger bullets such as 68gr. and 75 gr.
I have read that a 75 gr. bullet should be hand fed due to it's length.