Home Forums Hunting & Shooting Ask The Gunwriters Minimum amount of bullet seated in the case neck?

A few months ago I managed to snag one of last year's Ruger 1V's in .220 Swift and I have just started playing with it. After following a few discussions here about twist (this one is 1:14") and bullets that may not stabilize I said the heck with it and picked up some 40gr NBTs. The shop didn't have any 50gr's at the time and figured I wouldn't have any problem stabilizing these. And the most I will ever do with them is paper and small varmints (crows, squirrels, feral cats); one day it MIGHT see a coyote.

With some supplies in hand, I got home, checked the CBTO distance with the Hornady comparator/OAL tools and went to putting loads together with some RL15. And that leads to my question. With the bullet seated 0.005" off the lands there is only 0.100" of the bullet seated in the case neck (and since it is a boat tail, some of that length isn't even in contact with the case neck). For the heck of it I did shoot a few like this to see what it shot like--accuracy was supperb. However, I know these need to be seated deeper. As they are, a little mis-step in handling them and runnout is pretty easy to mess up.

Trying to do some research on minimum length of bullet that needs to be seated in the neck isn't the easiest thing as about the only consistent "rule of thumb" I have come across is "one bullet diameter deep." With this rifle and this bullet, seating to that depth gives me a jump of 0.123". Quite a jump. I haven't shot the new loads that are seated deeper yet but hope the accuracy stays.

All that said, is there a more consensual "rule" about minumum bullet seated in the neck or is this another of those vague handloading principles with no real rhyme or reason?

Am I overthinking this? Do I need to just rock on with them seated 0.1" deep in the case neck?

You can certainly experiment with deeper seating to enhance cartridge integrity, but the one caliber deep thing is certainly not necessary.

Examples: 300 Savage and 300 Winchester don't even have one caliber of neck.

I agree with MM. In a single, it wouldn't bother me much with the intended targets you suggest. My 22-250 is a single shot action and I always seat to lands regardless of neck bearing. For my big game repeaters, I personally prefer at least .25 and if that means jump, it jumps.

On another note, Wby, Tikka, etc have pretty much proven jump isn't a bad thing.

My 6.5x257AI might have a .1"grip on the 140gr Bergers seared .005" off the lands, but they feed well and shoot straight. As such, a tenth inch with .22 cal bullets should be just fine, especially if the accuracy is there.

I keep coming back to this. I'm not scared to seat deeper as long as the accuracy stays there. Currently seeing bullets touching @ 100yds with them seated 0.005" off. If that stays (or possibly improves) by going deeper, no big deal. I just haven't shot any yet with them seated deeper to confirm.

I guess in my head I just can't get around the big advantage of a single which is the ability to seat out as far as necessary to get close as you alluded to in your previous post. I guess I will either get over it or start trying heavier bullets so I can seat deeper and get close to the lands...after all, isn't that what a true looney would do?

If it makes you feel any better, my 22-250 single screams with 55 NBTs and it's a 14 twist as well. Heck, it even shoots 60NPTs and 70g Speers fairly well.

WE,

55 Blitz Kings are another that shoots decent in my 14 twist. Not quite as well as 55NBTs, but plenty good enough.

I wouldn't fret 1/2 caliber deep seating. Yes, it seems wrong and it seems like the bullets will easily get knocked out of wack, but if the gun shoots the loads well don't mess with success.

A friend had a wildcat 6.5mm based on the 5.56R case in his contender that had at most 1/8" neck, so less than 1/2 caliber and it shot bughole groups.

I think you already answered your own question. They shoot well, and it's a Ruger #1 so you don't need to worry about feeding or bullets coming loose in a magazine.

My #1 in 22 Hornet is the same way; best accuracy is with bullets barely seated in the case. I can actually pull the bullets out by hand. As long as the neck tension is consistent, it seems to work very well.

I haven't proven it, but have a pet theory that concentricity in bullet seating is less important when bullets are seated close to the lands with very low neck tension. With a bullet that fits the throat, concentricity issues seem to be auto-correcting because the case doesn't have enough grip to force the bullet out of alignment.

The rule of thumb for minimum seating depth is one bullet diameter. The main thing I would be concerned with is having enough neck tension that the OAL stayed consistent.

You are describing the "gimble method", against the lands, almost zero neck tension. It was very popular with benchrest shooters in the last 70's and early 80's.

Quote: "The rule of thumb for minimum seating depth is one bullet diameter."

This rule of thumb is for rugged hunting ammo in magazine-fed rifles.

For single-shots, varmint and target rifles full caliber of grip is unnecessary. I have loaded several calibers with only .15" of seating depth, or neck-grip on the bullet with no problems. I am speaking of bullet shank in contact with the bullet; boat-tail distance doesn't count.

I haven't experimented with less than .15", which is the minimum I use in my magazine rifles. I don't have any single-shots in my arsenal.

For "rugged" hunting ammo I like to see at least .25", regardless of caliber, just as insurance against rough handling and being cycled through the action several times, perhaps, during an extended hunt.

I hadn't heard the name but yeah, that's sort of the same thing. A little different in that the benchrest guys were seating long and crushing (very lightly) into the lands; in the case of my Hornet above I'm not loading into the lands (throat is way too long) but as close as I can get and still hold the bullet in the case. Seems to work very well for a single shot action.

Actually they were not "crushing". The necks were turned to match the chamber is such a way that you could start the bullets by hand, and finish seating them when you closed the bolt.

I concern myself w/ the amount of bearing surface in the neck mostly to endure concentricity, although one coming loose under recoil is an issue in a bolt.

Of course straight necks help... Lee Collet Neck Sizer (hint) .

Unless you are really wanting to use the 40's for some reason, there is certainly no reason your rifle will not shoot 55 gr or 60 gr bullets with a 14 inch twist.

55 gr and 60 gr cup and core flat base bullets are easily stabilized in 14 inch twist barrels at velocities exceeding 3600 fps.

60 gr bullets with polymer tips and monolithic bullets such as the Barnes X are exceptions.

I have been shooting the Hornady SP 60 gr flat base in several 14 inch twist 22-250 barrels since 1978.

Sierra also used to make, (maybe they still do) a 63 gr semi-spitzer which was designed for the typical 22-250 or 220 Swift of the day. They were all 14 inches from the factory in those days.


Your typical 14 inch twist in a 223 might not generate enough velocity to give you the rotations needed to stabilize the 60 gr Hornady. I can not say, I have never owned nor reloaded for a 223.

But your Swift will deliver several hundred more feet per second than the lowly 223.

War Eagle


I wouldn't load them with only a 0.1" seating in the neck.

There is plenty more to think about.

I ran your stats through Quick Load which gave me:

.220 Swift
40 Grain NBTS bullet

40 grains RL15

Ready for this ???

46,733 psi.

3,906 fps.

No- it's not a mistake. You may want to chrono it.

That's a barn burner package of DYNAMITE alright.

And not necessarily a barrel burner.

I would like to see some after photos. They must look like mush !!!!!

You're better seating deeper and watching the runout carefully. It's more important.

0.1" is just too flimsy for comfort. I checked it on my Lyman digital dial caliper and it looks, visually, not what I would want or do.

Looks like you have lots of wiggle room to do other things but if you are happy don't fix what isn't broke. You're doing just super good already.

Beat me to it.