Sierra 69-grain bullets COL confusion

[wildcard6]

I've just started reloading 69 grain Sierra BTHP Match King bullets in .223 cartridges for a friend of mine and the first thing I did was put together a 'dummy case' to make setting up the seating die easier in future. I set the Cartridge Overall Length [COL] at 2.258" [or near enough to 2.26" for setting up the die], then went to the ADI load data for powder charges and found to my surprise that ADI lists the COL for this bullet at 2.235" - which is 25 thou SHORTER than what they list for the 60 grain V-Max bullet that I'm using for 300-yard matches.When I looked at how deep into the case the 2.235" seating depth put the bullet, it was down past the base of the shoulder! Minimum powder charge with AR2206H is 24 grains and when I loaded to ADI's specifications, I felt the powder crunching already! Maximum charge is listed as 26 grains [C] a compressed load, but I'm already compressing the powder at 24 grains! I've been using 55-grain bullets in my .223 for years and I just load them to 2.26" [SAAMI listed max COL for .223 cartridge] and they shoot brilliantly. I'm just hoping somebody has had some experience with these 69-grain bullets in .223 and has some input on seating depth/COL. I've been loading for another buddy who's using 80 grain Sierra BTHP MK bullets and I used the ADI specs of 2.55" COL as my guide [I made them 2.54"] and they shoot spectacularly well over 300 yards. In fact, I was worried that it may be a misprint on ADI's part so I checked to see whether there was a new edition of their data and guess what? I've been using 6th edition[2013] for yonks and they're up to the 9th edition [2016] now! They still show the 69 grain Sierra BTHP MK bullet's COL as 2.235". Input/ advice/experiences would be appreciated on this subject.

[Tiger650]

Same experience with both 2206H and 2208, I recently began loading the 69gn sierra in Lapua cases but have not yet been to the range.
I regard recommended COAL as pretty much useless information in that most folks, me included, adjust COAL to find best distance bullet to lands.
The evaluation loads I have are pretty much full neck engagement and 26gns does compress.
Prior to bullet seating I close case mouth with a fingertip and vibrate the case against against a vibratory case cleaner, this settles powder load a little but I still have compressed loads @ 26gns.
Preparing to move house so cannot find my COAL data but the finished rounds did fit easily into AICS spec magazines, I will go longer COAL without too much concern.
Maybe ADI's test barrel has a very short leade ?
My Remington certainly does not.

[SCJ429]

Reloading manuals always publish very short COAL, you want to seat your bullet out as far as you can to maximise the space in the little 223 case. Is your friend using a magizene or single feeding them? If using a magizene, then that will dictate your max lenght. The SMK is very jump tolerant and I have done OK with 100 thou off the lands.

Have you got a long drop tube?

[SCJ429]

I used 2.460 COAL for 69 SMK in a factory chambered Tikka T3.

[sungazer]

There will be a lot of people that disagree with this however. The magazine length of the 223 is really made for the NATO 5.56 rounds. The 223 made by factorys today have a much longer freebore Lead. This allows heavier and longer bullets. It also makes sure that there is less pressure. That is because as soon as the bullet moves forward the pressure is reduced.

Here is the bit to start an argument. That is why you can fire any 5.56 rounds in todays 223 rifles without any problem.

[in2anity]

I shoot these, a LOT, in 3p comp. It’s easily my favorite .224 pill. Magazine size is the limiting factor for me. Just seat as far out as you can, based either on mag length or lands. If possible, it’s best not to compress - hot loads are hard on your brass and your throat. They shoot just as competitively to 400m whether you load hot or mild (provided you are on a node).

[Stix]

I might be a bit out of my league here chiming in with these guys...but i dont really pay attention to COAL listings as a general rule...
I use mag length, distance to lands, & the length of bullet seated in the case (eg; when the depth seated in the case starts to get significantly shorter than the calibre), as my governing factors ...

Ive found these factors will generally keep you well within safe loading COAL's despite what is listed...

[wildcard6]

Many thanks to all who replied. All advice is good and much valued. I checked in my own .223 with a slip-fit case and the COL was 2.36". I will ask my buddy whether he wants to single-load or magazine-feed before proceeding. I finished making test rounds for him to shoot using 2.26" COL, and will get him to check for maximum length in his own rifle. Thanks again and Wildcard OUT.

[TassieTiger]

I be always been told to not shoot 5.62 in 223
Copied from a site -
On a .223 Remington spec rifle, the leade will be 0.085”. This is the standard described by the Sporting Arms and Ammunition Manufacturers’ Institute, Inc. (SAAMI). The leade in a 5.56 NATO spec rifle is 0.162”, or almost double the leade of the .223 rifle.

A shorter leade in a SAAMI spec rifle creates a situation where the bullet in a 5.56 NATO round, when chambered, can contact the rifling prior to being fired. By having contact with the rifling prematurely (at the moment of firing), chamber pressure can be dramatically increased, creating the danger of a ruptured case or other cartridge/gun failure.
The reverse situation, a .223 Rem round in a 5.56 NATO gun, isn’t dangerous. The leade is longer, so a slight loss in velocity and accuracy may be experienced, but there is not a danger of increased pressures and subsequent catastrophic failure.

sungazer?

[sungazer]

I dont have the numbers in front of me but I do have Military rounds and 223.

The Military has changed the type and weight of bullet it has used over the years but they all must fit in the magazine with some room to spare. The COAL of 57mm. If you take a 62 grn SS109 or M193 for example and the velocity it was made to be 3250 fps the pressure 52000psi. The COAL is 57mm.

According to NATO the proof pressure was 62366 psi *125% =77958 psi

If the lead or Free bore was longer it would mean a very long jump to the lands.

I can load 73 grn at least in a Howa 1500. It is easy to fire a heavier longer bullet faster in a 223. The accepted standard pressure is 60000psi proof 60000*125% = 75000psi

The Military is known to save every dime they can and cut corners at every turn. Private enterprise covers its arse and over engineers things to protect themselves against idiots.

I have not seen a difference in either weight or water capacity in 5.56 Vs 223 cases that is large enough to support any of the claims that abound on the internet. There are differences between brands Cheap VS expensive. Even in high end expensive cases there are tolerances.

This is an interesting video https://www.youtube.com/watch?v=BTgGhIcR_Mk

Custom target 223' are now shooting 80 and 90 grn bullets granted no one gives a toss about SAAMI as that is just irrelevant. There are also 90 grn Hunting Rounds that are made for 223.

[TassieTiger]

Fair enough - my query was one of curiosity. I have no current reason to try 5.62 but understand why some might. Those top end pressures worry me - despite over engineering, especially when I let other shoot my rifles. But cheers for your perspective- explanation.

[sungazer]

The loads you typically load yourself are not going to be at those limits. I overstated the 223 pressure if you stick to SAAMI standards it would be 55000 psi proof pressure would be 125% of that. What I stated for the 223 is the more universally accepted manufactures rating.
From ADI you can see that you can push a 69 grn SIE HP at 2959 fps at 52900psi using 23.8 grn of 8208. Its very easy to get them going a lot faster without showing any pressure signs.

[wildcard6]

Update on load compression issues. I have been loading these bullets at 2.26" for magazine use. The first lot I loaded were using NEW ADI brass, but the next lot I loaded are in once-fired Neck Sized only cases and even 25.5grains fits comfortably into these cases, so 26 grains [listed as a compressed load] should fit without any powder-crunching. [AR2206H]. In relation to my original question about why the COL for 69-grain Sierras is so short, I think the discussion about .223 vs. 5.56x45 might be the answer. I suspect that the extra-short COL for this projectile is because it MAY be used in a 5.56x45 chambered rifle, loaded at maximum power/pressure and the extra jump to the lands may be insurance against an overload situation. One of the guys I'm loading for had some Sellier & Bellot 5.56 ammo that he was using in his Tikka and a couple of them pierced the primers on him. So it looks like the advice on NOT using 5.56 ammo in civilian rifles is correct.

[tophet1]

25.5 of 2206H under a Nosler 69 hpbt gives 2,975 fps in a 22" barrel. Just for reference.