Forstner ultra seating die inconsistent

[krprice84]

Ok, I posted this to another thread and I'm going to post up a flow up post I made below, I really am not happy about how this is working and I'm hoping you guys can help. I've been lurking here a long time and just now had the first question I couldn't find an answer for by searching.

I've been trying to use this forstner seating die I got from a vendor on here recently, to no avail. It is frustrating me to the point that I have gone back to using the Lee seater for now.... that bad....


What is happening is, I cannot maintain a fixed seating depth with it. Doesn't matter what I try. The charge I am using is 24.4 grains of H4895 in an IVI 5.56 case (resized then fire formed, body die sized and neck sized). The press is the Redding t7 turret press (I understand that some people say that a turret isn't as accurate or precise, this thing is built like a tank and seems to seat consistently with my Lee die). I am seating Berger 70 grain vld with it still, as I'd like to shoot through them before I move on to the Sierra 69gr bullets.


I am finding that the cartridge base to ogive measurement can vary from about 1.887 to 1.897 inches, measured with the Hornady attachment to my caliper. This variation is confirmed with my rcbs precision Mic, though of course it doesn't give the measurement in real numbers, the readout varies by the same amount.


I have tried everything from pulling the spring out, to screwing down the die slightly so that theshell holder barely contacts the die, I have tried polishing the seating stem with 5 and 1 micron sandpaper (this was a good idea anyways as it was leaving rings on my bullets), I just can't get this. On top of this, the seating depth seems to also vary with the amount of pressure I put down, #even though the press is over centre at the end of the stroke anyways and doesn't push farther.

The Lee die holds about 1.91 to 1.94 which is better but still not great. But to me that says it likely isn't the bullets (again haven't tried the smk yet, though the vmax seat fine enough on the Lee, within less than a thou either way generally.

I know guys swear by these dies but I'm about to throw mine out the window

 

[krprice84]

This post was on response to someone suggesting that the die seating stem may not match the bullet well (before I polished it the rings it made were up away from the ogive, certainly, further so than my Hornady or rcbs measuring devices measure from. Here is my response:

I just don't understand why the shape affects the ability to seat consistently. From my understanding, the seating stem may not contact at exactly the spot that is ideal, but since it is the same point on every one of the same style bullet, then how come that introduces problems?

The only thing I can think of is that it isn't really seating off of the ogive, but off of a spot closer to the tip where the shape isn't as perfectly controlled as the ogive. Then the second part of the issue that I can imagine is that the measuring device is not perfectly measuring off the ogive but at a point closer to the tip as well. It seems it is closer to perfect however, as when I measure the base of the bullet to the ogive using the Hornady attachment on my caliper, I can clearly see that they are within about half a thou, and that could be variance introduced by my hand pressure on the calipers.....

Regardless of that, my next question here is, assuming that the variance comes from the die seating off the curved part and not the ogive (the ogive being the meeting point of the curved portion and the bearing surface), then how does making a custom plug out of epoxy cure anything? To me that would make it worse, as now you have a plug that is formed to the entire curved surface, and the next bullet you seat clearly won't match that perfectly.

I think my solution may me to carefully machine out the seating plug on the stem to be more of a hollow cylinder instead of bullet shaped. It makes more sense to me for it to seat off of the place as close to the ogive as humanly possible without making the seater walls so thin that they are flimsy....thoughts?

 

[jlow]

You are probably seating off the meplat (tip of the bullet instead of the ogive). Take the seating plug out of the seater die and BTW also the Hornady OAL tool and insert a bullet it. Does the bullet go all the way in and touch the sides evenly or does the meplat bottom out? If it bottoms out, then you have your answer in terms of the problem.

 

[krprice84]

Doesn't look like I'm seating off the meplat, before I polished the seating stem, the bullets were left with a faint ring around them about half way down the curvature of the bullet (halfway between the ogive and the meplat). When I look in the stem, it looks very deep, and when the bullet is in it, it looks pretty clear that it is seating off only the curvature (it might be a bit further towards the ogive than halfway, but certainly no more than 2/3 of the way AWAY from the meplat).

Also when the bullet is in the stem (removed from the die) the bullet can be held snug against the seating plug/stem and, when tilted, I can feel that there is no resistance from the tip hitting the sides, so again, it seems clear to me that, at the least, it isn't seating off of the meplat.

My understanding, however, is that the ogive to base measurement is very uniform from bullet to bullet for any good match grade (or even any good quality in general) bullet. The ogive to meplat is less uniform, and impacts the accuracy/precision of the bullet very little. I used to take this to mean that the distance is less uniform, without thinking about shape, but it occured to me that the shape may also be affected. If the distance is longer, it would follow that either a) the meplat is smaller for the longer bullets or b) the curve has a smaller radius. I really find it hard to imagine that the radius would change, as this should be pretty static within a given die (and I would imagine that the dies themselves are machined to pretty damn tight tolerances, regarding this curvature). The size of the meplat and distance from the ogive being variable makes much more sense - the meplat end of the forming die is likely an open end, ending in a very small hole for air to escape. This would mean that as the length of the bullet varies (via the ogive to meplat distance changing) the only change would be the size of the meplat and how far into the die it is created. This *shouldn't* change the way the bullets are seated, however, as they are all seating off an area far enough from the meplat that it should be pretty darn consistent.

My next question/theory is, how consistent can one get with a good turret press? I always considered this press to be *very* strong and consistent, but recently I noticed that, when sizing, there is very (very) slight flex to it. I *cannot* imagine that this flex would be present when seating a bullet - the forces involved are miniscule in comparison. But could it be the case? What else could be causing this? I'm getting very frustrated with this - what press is generally used for making the best ammo? The Forstner Co-Ax press?

Thanks very much!

krprice84

 

[jlow]

OK, good! We managed to eliminate one possible problem so that is a good start.

About uniformity of good match grad bullets in terms of base to ogive measurements, the answer is no. I don’t use Bergers but have heard others that do mentioned the variance. Before you blame the press, my suggestion is for you to use your Hornady OAL tool and measure and sort your Bergers using base to ogive measurements. I think you may be surprised. The rule for precision reloading is “trust but verify”.

 

[Dusty Stevens]

I am finding that the cartridge base to ogive measurement can vary from about 1.887 to 1.897 inches, measured with the Hornady attachment to my caliper. The Lee die holds about 1.91 to 1.94 which is better but still not great.

are you sure youre looking at the numbers right? looks to me like the lee has .030 variance where the forstner has .010- maybe im looking at it crooked.
btw it is not your press. it seems to be built like a tank cause it is

 

[KMart]

When you are seating the bullet, is your stroke on the press handle a slow steady one every time or do you on occasion jam one in hard and quick?
I have found that a slow steady stroke without bouncing it hard at the bottom will give consistant results.

 

[BoydAllen]

Here is something that you can try. Set your die up so that the body makes light but definite contact with the shell holder. Shorten the sliding sleeve just enough to make the case push the sleeve instead of the shell holder, see if you can find a little stronger spring to return the sleeve.

The next part is a little more involved. put 50 bullets into a loading block that is shallow enough that you can pick them up easily after they are in place. Make a table With columns for bullet number, .17 ogive to base, and a .22 caliber to base. After you finish filling in the measured data, subtract the .17 ogive measurement from the .22 and enter the differences in the last column. The point is to look at variations in the distance from where the stem contacts to where the proper caliber tool contacts.

Another thing that will cause variations in seating depth is differences in seating force. Taking steps so that this is more uniform will help this.

Turret presses are more springy, than O type. This can contribute to variations. Try the same setup in both types to see if there if there is a difference in the results.

 

[savagedasher]

Your problem looks like to me is your trying to seat a bullet on the powder. depending on the seating depth you case is 105% to 107% full. Larry

 

[LRPV]

Your problem looks like to me is your trying to seat a bullet on the powder. depending on the seating depth you case is 105% to 107% full. Larry

+1

 

[krprice84]

I am finding that the cartridge base to ogive measurement can vary from about 1.887 to 1.897 inches, measured with the Hornady attachment to my caliper. The Lee die holds about 1.91 to 1.94 which is better but still not great.

are you sure youre looking at the numbers right? looks to me like the lee has .030 variance where the forstner has .010- maybe im looking at it crooked.
btw it is not your press. it seems to be built like a tank cause it is

Ahh you are right, they look that way, but had I written them properly it would have been better. The Lee was between 1.891 and 1.894

 

[krprice84]

When you are seating the bullet, is your stroke on the press handle a slow steady one every time or do you on occasion jam one in hard and quick?
I have found that a slow steady stroke without bouncing it hard at the bottom will give consistant results.

Slow and steady every time. Though I do notice that if the cartridge comes out long, I can sometimes put it back without adjusting the die and push harder, though still slow and steady, and get it down a few more thou

 

[krprice84]

Here is something that you can try. Set your die up so that the body makes light but definite contact with the shell holder. Shorten the sliding sleeve just enough to make the case push the sleeve instead of the shell holder, see if you can find a little stronger spring to return the sleeve.

The next part is a little more involved. put 50 bullets into a loading block that is shallow enough that you can pick them up easily after they are in place. Make a table With columns for bullet number, .17 ogive to base, and a .22 caliber to base. After you finish filling in the measured data, subtract the .17 ogive measurement from the .22 and enter the differences in the last column. The point is to look at variations in the distance from where the stem contacts to where the proper caliber tool contacts.

Another thing that will cause variations in seating depth is differences in seating force. Taking steps so that this is more uniform will help this.

Turret presses are more springy, than O type. This can contribute to variations. Try the same setup in both types to see if there if there is a difference in the results.

Not sure I understand the die modification. You mean permanently shorten the sleeve? Not sure I can do that accurately. But you mean to shorten it to the point that the case shoulder pushes up the sleeve and not the shell holder? Trying to understand what this would accomplish though? The sleeve doesn't have anything to do with seating, it's only a guide, isn't it?

As for measurements, you suggest getting a 17 caliber comparator to do this? Not a bad idea to check the consistency between bullets, for sure. Does the die seat the bullets at about .17" diameter?

Seating force is as uniform as can be.

The turret press I an using is not a standard one.... It us built like a tank. I can't imagine that the small force involved in seating a 22 caliber bullet would flex it?

Thanks for the ideas, I'll look into it more and try to find a comparator to check the bullets. Might modify the seating stem and see where that gets me though

 

[Patch700]

You are correct in that the sliding sleeve is a guide , one that needs to do its job prior to the actual seating of the bullet.

Is it possible you have the body of the die a tad too high and it is in fact starting the seating procedure before the case is fully supported? I don't believe if it were the case that it would be giving you discrepancies in your bto numbers but it'd certainly effect the purpose of a sliding chamber seating die.

If you are in fact seating on top of a compressed load you might try loading a batch of say 10 or 20 using a drop tube and then seat them extremely long and see if you are still getting the variances you mentioned.

 

[jlow]

Krprice84 – that “Hornady attachment to my caliper” OAL gauge you mentioned in the OP can be used to measure bullet base to ogive length. Just put the bullet instead of the loaded round in there.

 

[savagedasher]

Your problem looks like to me is your trying to seat a bullet on the powder. depending on the seating depth you case is 105% to 107% full. Larry

Your about 1 1/2 grain over in powder charge for 100% case fill . The reason they aren't seating right your crushing the powder. Load a few with 1 1/2 gr less. Larry

 

[krprice84]

You are correct in that the sliding sleeve is a guide , one that needs to do its job prior to the actual seating of the bullet.

Is it possible you have the body of the die a tad too high and it is in fact starting the seating procedure before the case is fully supported? I don't believe if it were the case that it would be giving you discrepancies in your bto numbers but it'd certainly effect the purpose of a sliding chamber seating die.

If you are in fact seating on top of a compressed load you might try loading a batch of say 10 or 20 using a drop tube and then seat them extremely long and see if you are still getting the variances you mentioned.

Not possible the die is set too high, I have tried setting it up so it is touching the shellholder, so it is causing the press to lightly cam over, and so that the die is set up so that the micrometer is right at around 0 when the depth is about correct. Have also tried it with the spring not inside (what does the spring even do? Seems pointless to me....).

Also, what does a drop tube even do? I don't get it....It doesn't make sense to me that having the powder fall a couple inches extra that it could do anything?

I might try setting up dummy rounds tonite and see how it goes....if they seat fine I know it's my powder. Quickload says that the load should be about a 96 percent fill but in reality it is closer to 100... I can hear the powder move a little when the bullet seats, but then after it is seated I can also still shake the cartridge and hear the powder ever so slightly, so it isn't compressed really hard. Will try and report back

 

[krprice84]

Your problem looks like to me is your trying to seat a bullet on the powder. depending on the seating depth you case is 105% to 107% full. Larry

Your about 1 1/2 grain over in powder charge for 100% case fill . The reason they aren't seating right your crushing the powder. Load a few with 1 1/2 gr less. Larry

Case capacity (water volume) is 30.1-30.3 grains of water. Can't recall the powder density, but like I say, quickload says it shouldn't be compressed in these cases. How are you determining that they are 1.5 grains over? Like I say, I can hear powder shake inside, but I can also tell that the powder is being moved aside in the case when I seat. Think that's the problem? Will have time to test out the theories later tonite

 

[krprice84]

Krprice84 – that “Hornady attachment to my caliper” OAL gauge you mentioned in the OP can be used to measure bullet base to ogive length. Just put the bullet instead of the loaded round in there.

Yes, but how do I measure the 17 cal point?

 

[Patch700]

What the drop tube does for you is so long as it is long enough (you may in fact need to fabricate one that is 6") is it will sometimes allow more room in the case , which in your instance could be the culprit.

Yes a drop tube will essentially pack the powder tighter even though it may only be dropping it between 3 or whatever length you desire.. I've used drop tubes as long as a foot allowing me to gain another 2 grains of powder in a case that was burning 7828.

If you don't have access to a drop tube are you at least able to seat the bullets long enough so they are not touching the charge? If so try seating them that long and if the problem goes away you know that a drop tube is in your future for that particular load.

Good luck.