Very short col/throat length problem?? advice needed

S

stalkuk

Inactive
Started ammo development for New rifle...

Howa 1500, .223 Remington, 1 in 9 twist, 24" heavy barrel, using viht N140 (it's all I can get regularly since most of the U.S. stuff got banned in the UK a few months ago) but I've had good results with it before so....

I'm loading 55gr for hunting and 69gr for target. I'd like to push the range as much a possible just for the challenge and was going to try 75gr bullets next but...to the point

Measured the max col of the 69gr using the hornady col length gauge, checked it since then too. Made up the first few rounds with starting powder weight and seated 0.020" off the lands. When I checked them against the reference data col (to the tip) they are 0.050" shorter than the reference length. So I've got a lot less space for powder. I'm experienced enough to work up the loads checking for problems as I go but...

With having such a large amount of space less for powder does that mean I will not be able to push the longer 75hr heads out to say 800yards or maybe even struggle with the 69gr heads even to 600yards? Or will the pressures be enough?

Just asking before I buy bullets I'll never be able to get where I want them to go.

Thank you for any support
 
Welcome to tfl!

Measured the max col of the 69gr using the hornady col length gauge, checked it since then too. Made up the first few rounds with starting powder weight and seated 0.020" off the lands. When I checked them against the reference data col (to the tip) they are 0.050" shorter than the reference length. So I've got a lot less space for powder.
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I think you are overthinking things, because the math doesn't add up....

First off, Generally, the length listed for COAL (base of case to tip of bullet) is not the required length, it is the maximum ALLOWED length. It is the maximum over all length that should work through magazines, and should chamber (and be off the lands) for ALL rifles chambered for that cartridge.

Next, Seating a bullet shorter (deeper) CAN take up powder space, but, in your case, DOES IT?? I ask this, because I have no idea how much, if any, your bullet protruded into the powder space.

How much does the base stick into the case below the neck? How much of the case is USED by the powder charge?? 0.050" isn't a lot, in some situations. In other situations, it can be very important.

And you need to determine if it even applies.
 
Thanks for the reply, I'm hopefully you can help me think this through. I'm not new to reloading and have checked everything I've measured and checked it again. The reference col in the data sheet is 2.244". If I loaded my cartridges to that length the would be jammed in to the rifling by 0.030". 0.050" longer than they are when seated 0.020" off the lands. What I mean by less powder space is in general compared to the reference length.

You're saying the reference col is a figure that should be possiblel to be fired from ALL factory rifles? The figures are from vihtavuori and using the exact same bullets I have.

Thanks again....
 
I posted while you were posting as well .

First off, Generally, the length listed for COAL (base of case to tip of bullet) is not the required length, it is the maximum ALLOWED length. It is the maximum over all length that should work through magazines, and should chamber (and be off the lands) for ALL rifles chambered for that cartridge.
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Which seems correct

I think you are overthinking things, because the math doesn't add up....
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I agree because if a 75gr bullet seated .020 off the lands is .050 shorter then the book recommendation . You would never be able to chamber a factory cartridge that uses the 75gr or the 77gr bullets because they are seated to that book COAL ??? That would mean your chamber is out of spec . So this leads me to ask what is that recommended COAL you are basing all these numbers on ? Is it 2.260 or longer then that because it sounds like you are saying the 75gr bullet seated .020 of your lands has a COAL of 2.210 is that correct ?

What method are you using to find "your" max COAL number ?
 
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My standard advice is to load up a dummy bullet in a sized case, seat it .050 longer than spoecified (keeping in mind 223 is used in Semi Auto so unless they tested in a bolt or have a separe bolt and semi auto listing - mag length on a 223 for semi auto dictates max not the throat.

Take your case, very gently close the bolt, if said bolt stop before it can be close, then you know its too long for THAT rifle.

You may need to tap the bolt handle to get it to come out, some bullets will actually stick fairly hard even gently closing.

Repeat until the bolt cloases (that may really stick one and you have to use your brass rod down the muzzle to tap out.

Repeat until no stick. Do another one, clean bullet, any marks on the Ogive? If so its right in the lands and sooner or alter a slightly longer Ogive will stick.

Move it back .020 and you have your staring point.

The tools can give you different results and readings.

I use the Hornady Ogive tool for my case lengths, I seldom measure a tip length as those vary far more than Ogive which also varies a bit.

The technique is only good for that bullet type from that MFG.
 
It's a 69hr bullet. I measure using hornady bullet comparator too but checked reference col to tip. Ref is 2.244" these measure 2.194"!

Seems I've either got a serious chamber problem or have dramatically got my measurements wrong. I'll do them again but have done this many times before and never had an issue.

I'll also try the dummy bullet idea.

Thanks
 
"...in the UK..." Best to put location in your personal settings. Where you are affects a great deal.
"...seated 0.020" off the lands..." Forget that until you have worked up a load. The whole off-the-lands thing is a load tweaking technique that is 100% trial and error. (Every rifle chamber is different and the off-the-lands distance will be different in everyone of 'em. There is no set standard distance that applies to every rifle.) Isn't really needed either. Just use the Max OAL given in your manual and you'll be fine.
Pick one bullet weight and work up the load for it, then work up the load for whatever other weight you want. The 1 in 9 twist will likely prefer heavier bullets than a 55 though. The brand of bullet doesn't matter. You load for the weight, not who made it.
The Hornady Bullet Comparator doesn't measure anything. That's just a gauge. Use your vernier calipres. OAL is measured from the pointy bit of the bullet to the flat part of the case. SAAMI(North America and I think Japan, where your rifle was made, Standards. Vs CIP that's Europe) Max OAL for .223 is 2.260". Minimum is 2.125". Neither has anything to do with the bullet weight.
"...either got a serious chamber problem..." Highly unlikely.
"...find "your" max COAL number..." You don't 'find' that. You set it.
"...Hornady Ogive tool for my case lengths..." No ogives on a case. No ogives required when OAL is measured correctly. Ogives only apply when fiddling with the off-the-lands stuff after working up the load.
 
First: I would determine the distance from the lands to the bolt face, and then:rolleyes: I would determine the two diameters of the barrel.

F. Guffey
 
Forget that until you have worked up a load. The whole off-the-lands thing is a load tweaking technique that is 100% trial and error. (Every rifle chamber is different and the off-the-lands distance will be different in everyone of 'em. There is no set standard distance that applies to every rifle.)
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.020 is a common measurement for that purpose of starting.

It keeps you out of the lands safely (avoiding pressure issue if up on the high end) and can be adjusted latter if desired.
 
The whole off-the-lands thing is a load tweaking technique that is 100% trial and error. (Every rifle chamber is different and the off-the-lands distance will be different in everyone of 'em. There is no set standard distance that applies to every rifle.
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lately I have been having good luck by starting with the Berger Seating test

Getting The Best Precision And Accuracy From VLD Bullets In Your Rifle

it say's VLDS but it works just fine with Nosler and Match Kings also. I modded it to where I do the test at .075, .050,.025 , and 0.0. Five shots at whatever range you feel comfortable with at or past 100 for groups. On calm days I shoot it at 300 but if windy or lots of mirage I pull back to 100 becasue in this test tight groups is what you are looking for with the least amount possible of shooter error. So far I have tested four bullets. Berger 80's - .075 off, 80 SMK's - kissing the lands, 123 Nosler CC's .050 off, and 142 SMK's - jury is still out on that one.

Once I do that I do a standard ladder test with the chosen powder and if needed tweak the depth and primer. If you plan on shooting past 600 look for a flat velocity node using Newbury's OCW method or a chrono
 
Anyone saying forget the whole off the lands thing is not reading the thread correctly. Forgetting that means based on the OP your are recommending the op start by JAMMING the bullet into the lands ?? Is that really where you recommend someone start a new load ????
 
I don't think anyone is saying that it is irrelevant MG, just that there is no one set distance that works for every bullet and barrel. Al least that is how I read the posts
 
Stalkuk,

Whose 69-grain bullet is it? Did the reference COL come from that bullet's maker? If it is for someone else's 69-grain bullet, it may not work. Different ogive radii make for throat contact points that are at different distances from the bullet base.

To 44 AMP's point, the seating depth is a good piece of information to put out there.

Seating Depth = case length + bullet length - COL

Use the standard maximum case length rather than actual case length so the capacity is standardized without trim variation being included, so for 223 Remington:

Seating Depth = 2.260" + bullet length - COL
 
Unclenick said:
Whose 69-grain bullet is it?
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Good point UN , I mistakenly assumed these are 69gr smk . That may explain the numbers and why they are not what I’m used to seeing .
 
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I think there is something screwy going on with your measurements. I have a hard time believing Howa made a rifle that wouldn't chamber a round within the max stated COAL, unless you are using some strange short noses truncated bullet profile.

I suggest making a dummy round with a "loose" neck (and no powder or primer) and slowly clambering it with the bullet seated very long. This allows the lands to push the bullet back into the case. Gently pull the case out of the chamber and check the length. this is your max OAL.
 
So start .020" off the lands with a moderate powder charge and shoot the gun.
Forget OAL, don't worry about chamber spec, work with what you have.
Adjust by whatever programme serves your needs.
I doubt .050" will keep you from reaching 600 yards, but I think the 75s will serve better, especially if you are trying for 800.
 
I meant to ask earlier, when you seat deeper is the shoulder of the bullet getting below the case mouth? The shoulder is where the ogive starts to come away from the cylindrical, full diameter bearing surface portion of the bullet. If not, you are still within this bullets normal loading range. If you have to go below that and this bullet is not a VLD or other special design, then something is, indeed, off-kilter.

Every once in a while you hear of a mass manufactured barrel that has been reamed with a roughing reamer but not a finishing reamer. The rougher doesn't cut the throat, so even if they are accidentally run in to produce full headspace, the throat would be short. But only someone with a borescope or who makes a chamber casting can tell you for certain.
 
stalkuk said:
It's a 69hr bullet. I measure using hornady bullet comparator too but checked reference col to tip. Ref is 2.244" these measure 2.194"!
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Whose reference COL are you using? If it came from Viihtavuori, then that's the COL they used for that bullet to achieve the pressures and velocities they reported. Those may well have been tested in a pressure barrel, and have no direct relationship to any actual firearm out in the real world.

For an industry accepted COL, I refer to SAAMI. I realize that you're on the other side of the pond from me and that Great Britain doesn't subscribe to SAAMI specs, but these are all I have. Since the military version is a military spec, SAAMI doesn't have an entry for it under 5.56x45, so I had to look for .223 Remington. The SAAMI overall length for .223 Remington is 2.125" minimum to 2.260" maximum.

Your reference COL of 2.244" is within [American} industry tolerances, so the reference number you obtained from Viihtavuori is, as I mentioned above, nothing more nor less than part of the recipe for the load they provided. You said their data are for the exact bullet you are using, so the simple answer is that seating the bullet deeper will reduce powder capacity and increase pressure.

I don't see how that has any effect on how far you can shoot that bullet. It just means that you need a tad less powder to achieve the same velocity. I expect that the same will apply if you try moving up to 75-grain bullets. You'll have to seat deeper to keep the ogive off the lands, so start a bit low and work up. It's the length of the bullet that's mostly going to dictate how far you can shoot it accurately.
 
I assumed the reference COL he mentioned applied to a specific bullet. Sierra shows their 69-grain bullet seated to 2.260", the SAAMI maximum (as does Nosler, with theirs). Vihtavuori shows the Sierra bullet seated to 2.244" but Hodgdon shows the Sierra's seated to 2.235", which I assume they found necessary for some reason. But nothing as short as the OP arrived at. Most curious.

I've had bullets catch on the mouth of the freebore of a chamber before when using the Hornady gauge and give a false short reading. A bit of jiggling of the thing is sometimes necessary to get it right. I'm thinking the OP should take a starting load and seat a bullet to the full 2.260" and just see if the round chambers. Assuming it does not, then keep nudging it in in 0.010" steps until it does chamber. See where that is and go for an addition 0.020". See where that lands.
 
I suggest making a dummy round with a "loose" neck (and no powder or primer) and slowly clambering it with the bullet seated very long. This allows the lands to push the bullet back into the case. Gently pull the case out of the chamber and check the length. this is your max OAL.
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I don't use that method as the newer bullets tend to stick in the lands even with very slow gentle bolt closing.

Going about it the other way with a solid seated bullet works well.

I will add that at times I have had it stick enough to pull the bullet out a bit of the seating.

So its a good idea to do the Ogive reading before you chamber the dumby round, not after.
 
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