Bullet seating

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Ranman

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If one is seating a bullet with a cannelure, is it necessary to take the bullet down as far as the cannelure? I've measured the distance to the lands with a RCBS precision mic guage to determine optimal seating depth for bullets to be about .005" from the lands but if I seat the bullet so that the ogive is that distance from the lands the cannelure is not at the edge of the neck. Is this a problem??
Randy
 
Not a problem as long as you have adequate bullet in the case to maintain alignment and not back out under recoil. If this is for a lever gun though you may want to use the cannelure for crimping in. Depends on what you have to some extent.
 
Thanks for the feedback. I'm assuming that adequate length in the case means at least on bullet diameter? The rifle is a bolt action Tikka T3.
 
When I load for top accuracy I work up a load with the bullet firmly against the lands. When the rifle must function without fail, I try to choose a bullet with a crimping groove rather than the more typical knurled cannular and crimp the bullet in place.

When you choose your bullet's seating depth you should consider several variables Does the round need to function through the magazine? Is the bullet seated so long that it might pull out of the neck if you unchamber the round without firing it? How will the change of seating depth effect pressure when the round is fired?

Generally speaking, seating the bullet so that 1 caliber of shank length (excluding the boat-tail) is in contact with the case neck will prevent the bullet from sticking in the lead of the barrel. However, if the round must function through the magazine, properly crimping the bullet in place will uniform the bullet pull weight and aid accuracy as it would if the bullet contacted the lands. Having said that I will only crimp a bullet that has a cannular or crimping groove. When you change the seating depth from the recommendation of your manual, you are going to effect pressure. Seating into the lands will create the most pressure, so if this is your intention your loads should be worked up accordingly.
 
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I'd be cautious about going to a 5 thou ogive clearance - particularly if you are a novice reloader. You'll be hard pressed to maintain that clearance from round to round, and bullet lot to bullet lot. Going up against the lands can cause pressure problems, or loading problems in a crucial situation (hunting)
And for what reason? - as a novice you'll get better bang for your buck by learning to work up a load with various powders/bullet weights, etc, and learning to make consistent ammo.
Ogive clearance is over-hyped as an accuracy parameter in a hunting rifle. I load to about 40 thou off the lands - still much tighter than the cannelure, and I can easily get the accuracy I want (sub moa)
 
You can forget about the cannelure and crimping groove altogether and seat to the depth you want/need. Crimping is only required for heavy recoiling cartridges and lever actions. Mind you, pistol cartridges that headspace on the case mouth like the .45 ACP, require and feed better with a taper crimp. No roll crimping for them at all.
 
sunray said:
You can forget about the cannelure and crimping groove altogether and seat to the depth you want/need. Crimping is only required for heavy recoiling cartridges and lever actions. Mind you, pistol cartridges that headspace on the case mouth like the .45 ACP, require and feed better with a taper crimp. No roll crimping for them at all.
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Wrong again, crimping bullets with proper cannulars uniforms bullet pull weight and improves accuracy.
 
maynard said:
Who many BR shooters crimp?
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How many BR shooters use long slender cases of slow burning powders such as used in most hunting calibers?
& how many ever put more than one round in a gun at a time?
A light crimp can in many cases improve accuracy by giving a more consistant ignition & burn rate.

Quite a few hunters use a variety of diff makes of brass or brass fired an unknown number of different times in these cases quite often a light crimp will improve accuracy :)

I'm not advocating the use of a crimp but it can & does have it's place.

The suggestion from Cosmic is an excellent one when apply'd to hunting rifles!

I'd be cautious about going to a 5 thou ogive clearance - particularly if you are a novice reloader. You'll be hard pressed to maintain that clearance from round to round, and bullet lot to bullet lot. Going up against the lands can cause pressure problems, or loading problems in a crucial situation (hunting)
Ogive clearance is over-hyped as an accuracy parameter in a hunting rifle. I load to about 40 thou off the lands - still much tighter than the cannelure, and I can easily get the accuracy I want (sub moa)
 
I have never noticed the slightest difference in pressure, whether the bullet tightly hits the lands, or whether it jumps. The BR shooters don't have to crimp because they seat to tightly hit the lands, giving even release. And they load them up full tilt!
 
There seems to be lots of debate as to whether crimping improves the finished product. Other than adding an additional step is there a downside to crimping??
 
Ranman said:
There seems to be lots of debate as to whether crimping improves the finished product. Other than adding an additional step is there a downside to crimping??
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You work the brass at the casemouth more, could cause premature splits.
 
Reloading

cosmic said:
I'd be cautious about going to a 5 thou ogive clearance - particularly if you are a novice reloader. You'll be hard pressed to maintain that clearance from round to round, and bullet lot to bullet lot. Going up against the lands can cause pressure problems, or loading problems in a crucial situation (hunting)
And for what reason? - as a novice you'll get better bang for your buck by learning to work up a load with various powders/bullet weights, etc, and learning to make consistent ammo.
Ogive clearance is over-hyped as an accuracy parameter in a hunting rifle. I load to about 40 thou off the lands - still much tighter than the cannelure, and I can easily get the accuracy I want (sub moa)
Click to expand...

I would follow this advice, 5 thou is not enogh clearance and you will probaly blow the primers out. What bullets are you using?
 
Once you develope the load your rifle likes, then it is time to fine tune it with seating deepth. Some rifles shoot best with the bullet touching the lands, some like a little jump, some like a lot of jump.
 
maynard said:
Who many BR shooters crimp?
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Bench rest shooter do not feed rounds from the magazine, so there is no problem for them to seat the bullets out far enough to be in contact with the lead, and in this way pull weight is the same from round to round. When a cartridge must be short enough to feed through the magazine, crimping the bullet, providing it has a cannular, is the best method of uniforming the bullet pull weight.

Edited to add, I see H4831 beat me to it.
 
I aim to seat for 15thou off the lands, but it will depend on how much room you have in the mag.

my 300WM max OAL is limited by the mag to 3.500" so its a bit further off the lands (about 55thou)
 
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