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Discussion Starter · #1 ·
Read a artical the other day stating that light grain bullets could be seated as shallow as .080 in the neck with a tight neck tension and be safe. Can't say that I've tried it but sounds a little shakey to me. My question is, can you go to deep and still be safe? I load a lot of 6.5 stuff and if you use heavy bullets you need to set them deep or you can't get them in the magazine. Iv'e set them below the shoulder with no ill effects but always wonderd if this could cause trouble.
 

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Seat bullets where you want.

Seating deeper than tested data will raise pressures, how much depends of a LOT of factors.
You are reducing the initial volume that the gunpowder burns in. Burn the same powder in a smaller space, pressure increases.

What advantage is supposed to be gained by hyper-shallow bullet seating?

I am not always able, but I generally try to work with the "1-caliber seating depth".
 

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.080"? Less than a tenth of an inch? Never happen on my bench. One caliber is a good rule, but I have done a little less with good results. Your 6.5s should be about .264" in the case neck and yes, long bullets often go deep, and those often just seat to spec "Max COL" or just short enough to fit the magazine.
 

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Pretty sweeping advice and I'd say not very good. A lot of things depend on the caliber, the rifle, the chamber and throat, what powder, primer, case bullet etc.

Its kind of like saying gasoline is good for cars. Might be fine for some cars but a lot more info is needed before making a decision.

My wild ass guess about where this comes from is guys who shoot for accuracy. If the barrel is throated for long heavy bullets than you can seat the shorter lighter bullets further out while still staying clear of the rifling. That can keep pressures down and allow higher powder charges to keep velocity up. I'd work loads up pretty carefully for myself rather than just taking advice.

Frank
 

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The key to safety is starting with a reasonable seating depth based on some logic and then working up your loads.

Requirements for seated bullets

1. The cartridge has to stay intact during handling and feeding.
2. If a magazine is to be used then the length has to work out of the magazine.
3. The bullet can not push down into the case with feeding or heavy recoil in a rifle.
4. The length has to be short enough to permit chambering.
5. The loaded round should not be so long that the bullet jams into the rifling and then pulls the bullet out of the case when extracted if the round is not fired.

I generally start with the length that touches the rifling. If this does not fit the magazine or give enough seating depth then I seat the bullet deeper.

I work up loads using the longest functional length. Long seating bullets may result in higher pressures so I start out at the greatest length(highest pressure) in my rifle. I can always seat the bullets shorter. Then I work up the load.

No I would never seat a bullet .080 deep. I like at least 1 caliber deep. If you run into lack of seating depth while trying to reach the lands there a few things you can do.
1. Sierra and similar tangent ogive bullets will contact the rifling faster than the secant ogive Hornadys.
2. Use a longer heavier bullet with a tangent ogive. Some round nose designs work better too.
3. Get rid of the stupid boat tail bullet if that is reducing the shank contact. I know everyone loves boat tails but for ranges under 300 yards you get nothing but easier seating in the case neck. Many rifles produce better accuracy at shorter ranges with flat base bullets.
 

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ireload2:
You state "1. Sierra and similar tangent ogive bullets will contact the rifling faster than the secant ogive Hornadys". I am not sure what you mean by that statement. Do you mean the bullet is traveling faster when it contacts the ogive with tangent bullets? I believe that is true, because the tangent ogive is shorter from base to a reference point on the curve than are the secant bullets and the bullet will have a greater distance to gain speed. If you mean the tangent bullets hit the rifling before the secant bullets, that is not true.

155 CC HPBT tangent ogive BTO................1.190 inch
155 Horn HPBT secant ogive BTO................1.229 inch

The secant ogive will hit the rifling before the tangent and for a given rifle, the secant will have more of the 308 diameter in the case. Not trying to start a pizzoff but only to clarify.
 

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Discussion Starter · #7 ·
It would never happen on my bench either,read this in one of the know it all mags. I would be afraid the bullet would fall out. They were using very light 22 cal. and getting as close to the rifeling as possible. Been loading for 30+ years and never heard of the 1 caliber seating rule , please explain it.
 

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I had to seat some light bullets very shallow because of feeding & chambering.
They worked.
Accuracy was the pits though.
I honestly don't know if it was the use of so light a bullet in that twist rate bore or the shallow seating though.
 

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It would never happen on my bench either,read this in one of the know it all mags. I would be afraid the bullet would fall out. They were using very light 22 cal. and getting as close to the rifeling as possible. Been loading for 30+ years and never heard of the 1 caliber rule , please explain it.
It is just a basic rule with modifications as needed for magazine length, need to reach close to the lands for accuracy, very short bullets, very long bullets, etc as discussed above... But to secure a bullet well...you might want to seat it as deep as it is wide (1 caliber deep in the case neck). .308 bullets seated .308" deep, 7mm bullets seated .284" deep and so on.
 

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That's my usual rule.
Using .311 bullets of 125 Gr in a .303 as an experiment you just couldn't get them to function without seating very shallow.
Like I said it was just an experiment & IMO it failed because of the terrible accuracy.
 

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There is more than one thing that restricts contact with the rifling when the bullet is seated.
1. The longer Hornady spire point plus the length of the case may exceed the magazine length before it contacts the rifling. That has zero to do with base to ogive, rather it is ogive to tip that causes that restriction. Try seating a spire point bullet in the dinky short magazines of a .30-30 cal rifle in 788 Rem or 340 Savage. The spire requires relatively deep seating compared to the blunt bullets normally used in the .30-30. The longer point/short magazine combo causes ogive band that contacts the rifling to be pushed deeper toward the case.

2. Even when you have a longer magazine sometimes you never get enough shank length because a boat tail takes up half of the shank length with a short bullet. You cannot count the length of the boat tail in a Base To Ogive measurement. It does not provide any grip for the case neck. So a short 155 grain 30 caliber bullet with a long pointy nose and a boat tail is one of the worst design combos from the hand loader's view point. You have little bearing surface for the case neck and the bore.

So yes I stand by the statement that a flat base Sierra bullet will contact the rifling earlier in the bullet travel if it is fired from a rifle with a restricted magazine length. This occurs in the .30-30 mentioned above, in 700 Rems with the 6mm Remington and some others.

I have had better success in a Rem 700 using a Hornady 165 grain spitzer. This is because the Hornady bullet picked had NO boat tail and the longer nose length was not a factor in the Rem 700 magazine. The long action Rem 700 magazines are all 300/375 H&H magnum length. They allow you to hang the bullet way out of the case. Only the base to the ogive is the limiting factor.


You will also find that many rifles that were originally designed for long heavy bullets or were just throated long for no particular reason. A boat tail will run out of shank before the rifling is reached with a short light bullet.
I hope this helps clarify the problems with bullets that are too pointy on both ends.

ireload2:
You state "1. Sierra and similar tangent ogive bullets will contact the rifling faster than the secant ogive Hornadys". I am not sure what you mean by that statement. Do you mean the bullet is traveling faster when it contacts the ogive with tangent bullets? I believe that is true, because the tangent ogive is shorter from base to a reference point on the curve than are the secant bullets and the bullet will have a greater distance to gain speed. If you mean the tangent bullets hit the rifling before the secant bullets, that is not true.

155 CC HPBT tangent ogive BTO................1.190 inch
155 Horn HPBT secant ogive BTO................1.229 inch

The secant ogive will hit the rifling before the tangent and for a given rifle, the secant will have more of the 308 diameter in the case. Not trying to start a pizzoff but only to clarify.
 
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