mow much under max mag length?

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Shadow9mm

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How much under max mag length?

I am working up loads for my new rifle. a Mossberg Patriot in 308.

After doing some measuring I believe the max mag length it about 2.860, as best I can measure....

Measuring the bullet to the lands, and backing off 0.020 leaved me at 2.865

I am going 0.020 off the lands to start, when I can. Its how I have done it forever. If we can please no arguments about where to start seating depth.

In any case the bullets a OTM and I am worried they could bind at the front due to the bullet style. How much should I measure back from my max estimated mag length?

My best guess at this point is 0.015 shorter than the mag? How much wiggle room do I need?

For reference 168g Hornady OTM
Hornady recommended COL of 2.800, which is a jump of 0.085 from the lands. I Want a little room to move back from there to adjust seating....
 
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Should I assume the cartridge is the .308 Winchester???

For reference 168g Hornady OTM
Hornady recommended COL of 2.800, which is a jump of 0.085 from the lands.
Click to expand...

If you are talking about the .308win, consider a couple of things...

First off, the jump to the lands only applies to your rifle, so lets put that on hold for now.

Next is the Hornady "recommended" COL of 2.800"...

2.800" is the industry standard max length for the .308 Winchester. With every bullet. That max length cartridge should work in every rifle's magazine, and be some distance off the lands in every barrel. That's its point. It MAY be the best length for a particular bullet and rifle, but that's not the point, the point is that it is the max length that should fit and work in everything.

You've checked, and you know your magazine is longer than that, and the distance to your lands is longer than that.

So, if you load to the industry standard MAX length of 2.800", what's your question??
 
He wants to know how much under mag length he needs to be to feed. Due to different bullet lengths and tolerances, I don't know of any universal rule of thumb for that. You might, for example, find you can set a plastic bullet tip closer to the magazine maximum than a round nose. But it is also the case with a lot of magazines that it is the location of the lips of the magazine that determine the maximum length for smooth feeding, as a bullet that fills the magazine can try to start sliding up the feed ramp before the body of the case is far enough forward for the magazine lips to let go of the round as it tries to finish chambering.

I think you are probably going to have to determine what your gun will tolerate experimentally. If it were me, I'd start by putting together a full magazine's worth of ammunition with my favorite 308 load in that gun 0.020" off the lands and see if I can get them into the magazine. If not, I'd turn the seating stem on my seating die in 0.010" and run the same rounds through it again and try again. When they fit, I'd try feeding and ejecting them. If I had hangups I'd go another 0.010" deeper and keep doing that until they feed reliably, then I'd try shooting them. Then I'd look at load ladders and try even deeper seating until I found the best accuracy depth I was going to find for it. Who knows? It might turn out 2.800" is what shoots best.

The above is the kind of problem I keep a Lee Handtool in my range loading box for. I usually take the micrometer seating die with it so I can do all the experimenting I need to with the muzzle pointing safely downrange.
 
One of the eternal questions, which is more important, the ultimate in accuracy, or dependability?

The answer, of course is situationally dependent.

personally, I tend to favor reliability over the nth degree of accuracy in most situations and absolutely in some situations.

One thing I will recommend, when testing for feeding, test from the bottom of the magazine. Pistols, especially, but other guns can have issues too.

If you're working with lengths close to or beyond standard max, completely fill the magazine with them, and see if they all feed properly.

I've seen it happen where the top or top few overlength rounds feed fine, but ones deeper in the magazine bind. So don't just put a couple rounds in the mag and call it good if they work ok. Load the entire mag and test them all. The last round needs to feed exactly like the first one.

Everything has tolerances, and when you're reducing the usual clearnces, everything needs to be tested fully.

I have yet to find a factory round loaded to industry max length, they are all at least a little bit shorter, to allow for tolerance variations in different guns.
 
Trial and Error ... bring your Lee Hand Press & seating dies to the range .
Don't give too much information ... knowing what round you are asking about takes the fun out of getting a correct answer .
Gary
 
Well I did some more measuring and loaded some dummies. seating the bullets to the lands the COL had a ES of 0.015. Measuring with my Ogive comparitor I only had a ES of 0.003. To me this means the ogive to tip length is roughly inconsistent by 0.012.... feel free to correct me if I am wrong.

In any case based on the OTM catching the mags, and the inconsistency in the tip lengths I decided to just load them to 2.800 so they would function reliably. I still have a good ammount of bearing surface left to play with seating depth to tune the load.

Based on the current seating depth I believe I have a jump of about 0.075. A bit more that I would like but I believe it gave me some extra velocity. Velocity was about 100fps above published for the load I am using. And that is with a 22 in barrel vs the 24in barrel listed in the test data. During testing today I had no pressure signs. I stopped 2.0g under max to stay conservative as I am using LC brass. Going to push to max next outing and see what she will do.

I did consider loading out farther and single feeding. I may do that in the future.

I guess I am just spoiled. My $300 30-06 TC Compass has enough room in the magazine to seat out to jam if I wanted to.
 
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Don't over think this. I simply load a single round to the max length that it will fit in the magazine. If it fits in the magazine and feeds reliably into the chamber without hitting the lands then that is where I load my cartridges. If it is too long I use the trial and error method to load it shorter until it fits.

I'll then load up a few rounds and go to the range. If they meet my accuracy standards then I've found my load. They almost always do. If not I can always reseat any unused loads deeper and continue experimenting. Since I can't possibly load them any longer unless I want a single shot, (I don't) there is only one direction to experiment.

I don't even know what my OAL is or distance to lands. If it feeds and shoots that is all I need to know.
 
44 AMP said:
Should I assume the cartridge is the .308 Winchester???



If you are talking about the .308win, consider a couple of things...

First off, the jump to the lands only applies to your rifle, so lets put that on hold for now.

Next is the Hornady "recommended" COL of 2.800"...

2.800" is the industry standard max length for the .308 Winchester. With every bullet. That max length cartridge should work in every rifle's magazine, and be some distance off the lands in every barrel. That's its point. It MAY be the best length for a particular bullet and rifle, but that's not the point, the point is that it is the max length that should fit and work in everything.

You've checked, and you know your magazine is longer than that, and the distance to your lands is longer than that.

So, if you load to the industry standard MAX length of 2.800", what's your question??
Click to expand...
Perhaps i am confused, but 2.800 is not the recommended or max length for every 308 bullet. Maybe i am just reading this wrong? There are shorter bullets, like 110 grainers. And there are longer rn hunting bullets that might jam into the rifling at 2.800. And at least one manual lists 2.810 Saami's max, even if most manuals go to 2.800?
 
I'm not sure if you're asking how much or meow much :D

I think you are probably going to have to determine what your gun will tolerate experimentally. If it were me, I'd start by putting together a full magazine's worth of ammunition with my favorite 308 load in that gun 0.020" off the lands and see if I can get them into the magazine. If not, I'd turn the seating stem on my seating die in 0.010" and run the same rounds through it again and try again.
Click to expand...

I think that is solid advice . The one thing I'd look for is the consistency of your COAL based on bullet tip variances . I load to mag length for my AR and 77gr SMK . To get all at a maximum of 2.260 some are as short as 2.250 . That's just because SMK's are IMO incredibly inconsistent as far as tip to baring surface which throws off my COAL consistencies . How did I find this out , by figuring out the exact same thing you are . I tried to get my cartridges to as close to mag length as I could and what ended up happening was there were some cartridges that ended up being to long do to those inconsistent tips . This resulted in the rounds binding up in the mag and failing to feed .

You'll need to load some up at mag length and see if they feed . What works for me is a visual look at the clearance because measuring always resulted in binding in the mag . I load the round in the mag and I need to see the gap between the bullet tip and mag . Now that does not need to be a big gap but if it's noticeable at a glance , I've got plenty of clearance . To answer your question specifically , minimum .010 short of mag length should allow all rounds to feed but .015 to .020 would almost guaranty they all feed well .
 
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zeke said:
Perhaps i am confused, but 2.800 is not the recommended or max length for every 308 bullet. Maybe i am just reading this wrong? There are shorter bullets, like 110 grainers. And there are longer rn hunting bullets that might jam into the rifling at 2.800. And at least one manual lists 2.810 Saami's max, even if most manuals go to 2.800?
Click to expand...
I am using the Hornady Manual. It lists the MAX Col at 2.810. However for the 168g OTM match it states a seating depth of 2.800. I am guessing that is because they are aware of the variances in the bullet tips and wanted a little extra wiggle room.

I did end up making a couple dummies and pushing them back until they fed properly.
The result was about 2.805. In this case I decided to seat the bullets at 2.800 as recommended to start out seeing at I was already way off the 0.020 off the lands I was looking for anyway.
 
Perhaps i am confused, but 2.800 is not the recommended or max length for every 308 bullet. Maybe i am just reading this wrong? There are shorter bullets, like 110 grainers. And there are longer rn hunting bullets that might jam into the rifling at 2.800. And at least one manual lists 2.810 Saami's max, even if most manuals go to 2.800?
Click to expand...

One can get too literal and lose the forest for the trees.

2.800" is the CARTRIDGE max length. Doesn't matter what bullet you put in it. Its not something you must load to, its a length you should not exceed. No, you aren't going to get there with short 110gr bullets. Why would you even try?

Longer RN bullets jamming into the lands if loaded to 2.800"?? should not happen. Going by SAAMI specs (chamber and ammo) you should be able to load a full wadcutter bullet to max listed length and not be jamming it into the lands.

That being said, SAAMI is voluntary and no maker of guns or ammo or bullets is required by anything to stay to SAAMI specs, if they choose not to.

Am curious, what manual(s) list 2.810" as the max length? My Lyman lists 2.800" and has for the 50 years I've been using it.
 
My current hornady manual lists the max col for 308 as 2.810 . Bit it lists different lengths by bullet in the specific load data
 
"Longer RN bullets jamming into the lands if loaded to 2.800"?? should not happen. Going by SAAMI specs (chamber and ammo) you should be able to load a full wadcutter bullet to max listed length and not be jamming it into the lands. "

Sorry, this is flat out wrong. And i ain't stating it as an opinion. Worse it could be actually dangerous for beginners who don't bother to determine at what point the bullet contacts the lands.

Much better advise would be to test every new bullet being used to see how far out you can seat it before it hits the lands, if it even does. And to test to see how it feeds.

The Saami max is 2.810 according to their drawings.
 
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Yes. The SAAMI spec is 2.810" max but the military spec for 7.62 NATO (same developmental parent as 308 Win) is 2.800" max and the CIP has 308 Win at 71.2 mm (exactly 2.800") max. So there isn't universal agreement on this number. Keep in mind this number is just used to determine magazine fit. There is no guarantee it is suitable for allowing any particular bullet to fit in any particular chamber. That's a separate issue.
 
I miss the days when life seemed simpler...:rolleyes:

The book said 2.800 so 2.800 it was. Used a loaded factory round to set seating for overall length...didn't care where the lands were, provided the bullet wasn't jammed into them, and that never happened loading "regular" bullets to or less than listed max length...

I've loaded RN bullet in 308Win, 150s, 180s, even 220s, all to spec length none ever hit the lands in any of the several rifles I had. Not saying it isn't possible, people make all kinds of unusual stuff today, but do, if possible, show me what .308 Win rifle and what bullet is hitting the lands when loaded to 2.800" or less? Please??

I will agree that loading specialty bullets and loading in target rifles means you can do other things that what one does in regular hunting rifles, but hunting rifles are what I load for. My favorite deer rifle in .308W won't do MOA, never has, never will, I think, unless I rebuild it into something its not. Does go less than 2MOA though, and does it with everything I put in it, and that's good enough for me, no deer has ever seemed to notice, either..:rolleyes:
 
"I've loaded RN bullet in 308Win, 150s, 180s, even 220s, all to spec length none ever hit the lands in any of the several rifles I had"

Am just curious as to what you mean by "spec length". Are you referring to 2.800, or a specific length for a specific bullet in a specific manual?

Thanks
 
zeke said:
"I've loaded RN bullet in 308Win, 150s, 180s, even 220s, all to spec length none ever hit the lands in any of the several rifles I had"

Am just curious as to what you mean by "spec length". Are you referring to 2.800, or a specific length for a specific bullet in a specific manual?

Thanks
Click to expand...
the specific bullet in the hornady manual
 
"show me what .308 Win rifle and what bullet is hitting the lands when loaded to 2.800" or less? Please??"

Wby Vangard.

Lapua 200 gr fmjbt hits lands at 2.730 in
Nosler 220 Ballistic tip rn hits lands at 2.692 in

Rem 150 rnsp core lok hits lands at 2.700 in. It is mainly intended for 30-30, but people use 30-30 bullets in 308 Win.

Speer 150 flat point hits lands at 2.640 in. Another 30-30 bullet

"The book said 2.800 so 2.800 it was."

Can i ask what "book" ? and what specific round noses you loaded to 2.800? Some round nose bullets appear to be designed with a tapered dia.

As a matter of interest looked specifically at a couple older reloading manuals. Most of them did not even list a COL or a max COL. Let alone go into finding the col by checking with a dummy round or other method.

thanks
 
Thank you for providing actual examples. Been hearing for years how "this can happen" but you are the first person I've talked to who actually had examples.

Interesting to hear the rifle was a Weatherby Vanguard. Their Mk V magnums have a reputation for a lot of freebore...I wonder that the Vanguard doesn't...or if it was just your Vanguard...?

Never used Lapua bullets and very few Noslers and none in the weight you mention

Have used a lot of Rem, Speer, Sierra, Hornady stuff, and have loaded the 30-30 slugs in .308 too. Never any issues, but let me clarify a little.

The book was the Lyman 45th edition (1970) and was the current book when I began loading. A round of Rem factory spitzer was used to set the seating die, as the calipers showed it to be just under 2.800" Used the same setting loading the RN bullets so they were a little shorter yet. Everything fit in the mag, and the chamber just fine.

Loaded some of the 150FP/RN .30-30 bullets too, those were seated so the cannelure was in the right place, but I didn't crimp (no need). Not sure the length on those, but absolutely well below 2.800".

Main rifle was a Remington 600 but that ammo also went through a custom Mauser, a model 70, and a BLR. Did not run the 180 RNs or the 150 FPs in my M1A, but they worked fine in all my other stuff.
 
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