General OAL Question for .223


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CJK8
September 24, 2011, 10:20 AM
I know max saami spec is 2.260". I have my die set up for 2.220 for one bullet. I bought some 55 gr v-max. Without adjusting the seating die, the OAL with the v-max bullet is 2.300" The round chambers fine in my rifle and is not touching the lands. That OAL seems awfully long. Are there issues with that long of an OAL as long as not worried about fitting in a magazine (this is for a bolt action i usually single shot). Since the roud is not touching the lands, People tell me it is fine...but still, 40/1000s over max saami specs....Thanks.

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rcmodel
September 24, 2011, 10:42 AM
It is generally a good idea to have at least one bullet dia inside the case neck.
I don't know how that figures out with your load, but that is what I would try to do.

The reason is not only to keep the bullet from falling out of the case.
It also will provide more consistent neck tension to get a good powder burn started.

rc

soloban
September 24, 2011, 11:31 AM
If the OAL is longer, that will increase the space inside the case and decrease pressure.

ranger335v
September 24, 2011, 12:30 PM
"If the OAL is longer, that will increase the space inside the case and decrease pressure."

True for small, high intensity hand gun cartridges but not for a rifle cartridge. Seating at or very close to the lands increases start pressure in rifles. The very small change in internal volume with deeper seating in larger volume cases with much slower burning powders reverses the situation found in little cases. Seating deeper, within reason, will allow a rifle bullet a running start at the lands and it's own inertia will help it engrave the rifling and keep moving at a significantly lower start pressure for a given charge.

Consistant bullet 'tension' (as it's normally defined) demands a lot more than seating a caliber deep. In fact doing that is impossible with a lot of cases. Many necks aren't a caliber long, nor do they need to be.

CJK8
September 24, 2011, 06:43 PM
I guess a follow-up question is if there is anyone out there loading rounds that are 2.300" or longer for their .223? I'd be curious to know how long .223 cartidges can be iin some peoples' rifles. I haven't tried to test my max OAL possibility in my rifle for this particular bullet. Thanks.

cfullgraf
September 24, 2011, 06:52 PM
I don't use Sierra 80 and 90 grain match bullets, but the Hodgdon loading data for them have over all lengths of 2.550" and 2.380" respectively.

ranger335v
September 24, 2011, 09:34 PM
General OAL Question for .223 --- I know max saami spec is 2.260".

I wonder why you say that? I've been doing this since '65, tens of thousands of rounds and dozens of firearms and cartridges. I have never even looked at a book OAL for anything, I find what each gun needs and use it to develop a load. Then I refine the seating for best accuracy.

Actually, SAMMI doesn't spec any OAL at all. They do spec the minimum chamber throat for specific cartridges but the gun makers are free to make those throats (and magazines) as long as they please. Many chambers are indeed longer than the SAAMI minimum so the limiting factor for OAL usually does become the magazine. Different nose shapes have different lengths for the same weights but our guns really couldn't care less where the point of the bullets hang in space; if the round will feed and chamber properly it's fine.

Various book makers sometimes (not always) specify an OAL but that's not meant to be a 'rule' for us to follow, it's just the OAL they used to develop the listed data. You will find that different manuals list different lengths for the same bullets. And a LOT of good loading data sources don't even suggest an OAL, it's just understood that we will have to find our own best seating depth.

CJK8
September 24, 2011, 11:12 PM
Maybe I incorrectly assumed the drawings in the links were sammi spec. If I was wrong, oh well...

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


http://accurateshooter.net/Downloads/sierra223rembolt.pdf

ranger335v
September 25, 2011, 09:44 PM
No, you just missinterperted what the SAAMI drawing actually means.

Whatever, do as you wish, your misunderstanding is harmless enough.

raddiver
September 26, 2011, 01:42 AM
I came up with 2.3 also when working it out for my rifle. Stevens 200. 2.350 - 2.355 seemed to be the average for me. So i back off a bit and went with 2.3.
I havent had a chance to shoot them yet, im hoping next weekend.

NCsmitty
September 26, 2011, 10:12 AM
COAL is a flexible number that is subjective for all bottleneck rifle cartridges.

In SA or AR 223/5.56 rifles, you will need to adhere to a max length that will function through the magazine, if that's your intent. On lighter/shorter bullets you should maintain a caliber depth to retain a decent neck tension as rcmodel alluded to.
Each rifle will have it's own sweet spot.



NCsmitty

amlevin
September 26, 2011, 11:38 AM
CKJ8-

I load all my ".223" ammo to 2.255" OAL. Of course I only shoot it through one of three AR-15's and this length assures me I have just about the longest OAL that will reliably feed through my mags (with an extra .005" for safety).

Bolt actions are an entirely different matter.

CJK8
September 26, 2011, 12:42 PM
No, you just missinterperted what the SAAMI drawing actually means.

Just curious then. What does the SAAMI drawing mean when referring to max and mins if not max/min SAAMI specs? Always here to learn. Thanks.

GLOOB
September 27, 2011, 08:28 PM
I load all mine to right about 2.3". As long as your rifles feed it, no biggie. You can always shorten the OAL later, if you get a new rifle that doesn't like 'em.

ranger335v
September 28, 2011, 10:32 AM
"What does the SAAMI drawing mean when referring to max and mins if not max/min SAAMI specs?"

Minimum magazine and action lengths, primarily for the rile manufactors.

Actual magazine, chamber and throat lenghts can be as much longer than the minimum as the makers wish.

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