Soft seating
- Thread starter ptf18
- Start date
In my experience, the work involved with soft seating is finding the right neck tension. I use .001-.0015". I get this number by measuring the case neck od before I seat a bullet, seat bullet, and measure again. The difference in the numbers is neck tension. Too little and the bullet won't be held at all by the neck. Too much crams the bullet in the lands and shoots like crap.
Try using as little as you can and reliably hold the bullet. This may require some experimentation, but will be worth the effort. When soft seating, the bullet is able to correct itself for throat erosion. Inconsistent seating depths are no longer a problem. This is also likely to give you ammo that will work well in multiple guns, assuming the chambers were cut with similar or the same reamers.
Try using as little as you can and reliably hold the bullet. This may require some experimentation, but will be worth the effort. When soft seating, the bullet is able to correct itself for throat erosion. Inconsistent seating depths are no longer a problem. This is also likely to give you ammo that will work well in multiple guns, assuming the chambers were cut with similar or the same reamers.
Imagine that...I have tried neck tension under .001". I thought it shot quite well. I agree with you that as long as you can't move the bullet with your fingers, it's probably enough.
Here's why I don't use that little tension: As a highpower shooter I have to work with many pieces of brass. Occasionally, at .0005 tension, I would find a piece of brass that gives zero tension, even though I neck turn. If I had only a hundred or less cases, I could basically sort those out and trash them. With the larger quantity of brass, it's harder to keep track of these things. Any accuracy difference in the two tensions was small to nonexistant in my testing, and the higher tension also gives a little more "durable" ammo for traveling and such.
Here's why I don't use that little tension: As a highpower shooter I have to work with many pieces of brass. Occasionally, at .0005 tension, I would find a piece of brass that gives zero tension, even though I neck turn. If I had only a hundred or less cases, I could basically sort those out and trash them. With the larger quantity of brass, it's harder to keep track of these things. Any accuracy difference in the two tensions was small to nonexistant in my testing, and the higher tension also gives a little more "durable" ammo for traveling and such.
AlNyhus
Silver $$ Contributor
I 'soft seat' bullets in both my BR .30 cal. guns. For consistent results, it's the only way to fly.
It's a snap to set up: I take an empty fired case, seat a bullet 'long' using .004 neck tension, polish the bullet with some 0000 steel wool, plunk it in the chamber and close the bolt. Open the bolt and remove the round. If you used a decent amount of neck tension,hence the .004 figure), the bullet stays in the case neck. With the polished bullet, it's easy to see the marks made by the lands.
Next, I seat the bullet another .005 deeper and repeat the process. Again, make sure and polish the bullet each time. I repeat this until the marks from the lands just disappear...then you know you're just a skosh back from the lands. A skosh is just a tiny bit more than a smiddgen.
When I'm at this point, I just back the seating stem out .030 and am good to go. This way, the bullet gets 'soft seated' when the bolt is closed, regardless of neck tension. It seems like .030 is a lot of 'jam', but the reality is that a bullet can only be 'jammed' so far into the lands, regardless of how much neck tension is used or how far out the bullet is. If you doubt that..just try pushing a bullet up your barrel with a rod sometime.
From this point, I can work with neck tension to see what the gun likes. In my .30 cal. junk, I've always found accuracy increases by using more neck tension. Also, there will be the occasional barrel that likes to have some 'jump' to the lands, but this is an individual bullet/barrel/chamber/action thing that you just have to sort out on a per gun basis.
For those that don't 'soft seat'...or 'hard seat' if you're using a goodly amount of tension, you should really try this method. It allows you to find a tune up quicker, as you have only one way to go with seating depth. I start with .002 tension and just fiddle with the powder measure first. Once I have the best accuracy with powder weight, I tighten up the neck tension .001 at a time and see what happens, keeping the powder charge that gave the best accuracy with .002 tension. As a last resort, I'll change seating depths...but that rarely needs to be done.
Using this seating method, I'll just check it occasionaly to see what the marks look like and adjust a wee bit if needed...usually about once or twice per season is all. If I sense that the gun is getting a bit loose, invariably the seating depth needs to be adjusted and the accuracy picks right up again.
Other calibers may need a different approach...the 6mm's seem to more responsive to seating depth changes, IMO.
Just my 2 cents worth on it... Good shootin'. -Al
It's a snap to set up: I take an empty fired case, seat a bullet 'long' using .004 neck tension, polish the bullet with some 0000 steel wool, plunk it in the chamber and close the bolt. Open the bolt and remove the round. If you used a decent amount of neck tension,hence the .004 figure), the bullet stays in the case neck. With the polished bullet, it's easy to see the marks made by the lands.
Next, I seat the bullet another .005 deeper and repeat the process. Again, make sure and polish the bullet each time. I repeat this until the marks from the lands just disappear...then you know you're just a skosh back from the lands. A skosh is just a tiny bit more than a smiddgen.
When I'm at this point, I just back the seating stem out .030 and am good to go. This way, the bullet gets 'soft seated' when the bolt is closed, regardless of neck tension. It seems like .030 is a lot of 'jam', but the reality is that a bullet can only be 'jammed' so far into the lands, regardless of how much neck tension is used or how far out the bullet is. If you doubt that..just try pushing a bullet up your barrel with a rod sometime.
From this point, I can work with neck tension to see what the gun likes. In my .30 cal. junk, I've always found accuracy increases by using more neck tension. Also, there will be the occasional barrel that likes to have some 'jump' to the lands, but this is an individual bullet/barrel/chamber/action thing that you just have to sort out on a per gun basis.
For those that don't 'soft seat'...or 'hard seat' if you're using a goodly amount of tension, you should really try this method. It allows you to find a tune up quicker, as you have only one way to go with seating depth. I start with .002 tension and just fiddle with the powder measure first. Once I have the best accuracy with powder weight, I tighten up the neck tension .001 at a time and see what happens, keeping the powder charge that gave the best accuracy with .002 tension. As a last resort, I'll change seating depths...but that rarely needs to be done.
Using this seating method, I'll just check it occasionaly to see what the marks look like and adjust a wee bit if needed...usually about once or twice per season is all. If I sense that the gun is getting a bit loose, invariably the seating depth needs to be adjusted and the accuracy picks right up again.
Other calibers may need a different approach...the 6mm's seem to more responsive to seating depth changes, IMO.
Just my 2 cents worth on it... Good shootin'. -Al
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