inconsistant ogive on 178 AMAX

[jbell]

I have just started shooting the 30 cal. 178 AMAX and have loaded 250 rounds with them. The first 200 were from a different lot # than what I have now. The first lot (which I dont remember the #) was very consistant, and shot well. I bought 500 more based on that. I started in this new lot and found the length from the base to the ogive is inconsistant. I found out of a random 50 bullets from lot # 2110062 that 40 measured 0.693 base to ogive and 10 measured 0.698. Now this may not sound like much but when loaded with my Redding comp. seater that is .010 difference in seating depth. I used a smaller compairator and measured forward of the ogive and found that the shape of the bullet is off. Its like it is more secant than tangent (its still tangent but just a bit more round). Has any one else found this? One other note all I have measured is these 50 bullets and each size was very consistant, there was very little deviation (less than .001) in each measurement. Its like they were made on 2 different machines with one having the incorrect shape. I haven called Hornady yet but plan on it, just for my own info not to complain.

 

[thefitter]

Re: inconsistant ogive on 178 AMAX

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jbell</div><div class="ubbcode-body">I have just started shooting the 30 cal. 178 AMAX and have loaded 250 rounds with them. The first 200 were from a different lot # than what I have now. The first lot (which I dont remember the #) was very consistant, and shot well. I bought 500 more based on that. I started in this new lot and found the length from the base to the ogive is inconsistant. I found out of a random 50 bullets from lot # 2110062 that 40 measured 0.693 base to ogive and 10 measured 0.698. Now this may not sound like much but when loaded with my Redding comp. seater that is .010 difference in seating depth. I used a smaller compairator and measured forward of the ogive and found that the shape of the bullet is off. Its like it is more secant than tangent (its still tangent but just a bit more round). Has any one else found this? One other note all I have measured is these 50 bullets and each size was very consistant, there was very little deviation (less than .001) in each measurement. Its like they were made on 2 different machines with one having the incorrect shape. I haven called Hornady yet but plan on it, just for my own info not to complain. </div></div>

I was told that the hardcore will buy ALL the bullets and powder for the life of a new barrel all at once for reasons like this.

 

[jbell]

Re: inconsistant ogive on 178 AMAX

That makes sence but I have a very bad problem, I cant leave well enough alone. I am always searching for a better way, and besides if I just stick with what works Ill never learn anything.

 

[thefitter]

Re: inconsistant ogive on 178 AMAX

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jbell</div><div class="ubbcode-body">That makes sence but I have a very bad problem, I cant leave well enough alone. I am always searching for a better way, and besides if I just stick with what works Ill never learn anything. </div></div>

Understandable. That is what makes the reloading aspect of this hobby addictive.

 

[vman]

Re: inconsistant ogive on 178 AMAX

I wish I had the cash to buy up that much in components.

I guess if you sorted your bullets in a tedious fashion you could group them all, and for the longer projectiles seat them 0.005 deeper.

 

[SPAK]

Re: inconsistant ogive on 178 AMAX

With the AMax bullets, I usually set my seater about .010" Longer than my target seating depth. Measure and then finish seating to my final depth. It doesn't fix the problem of ogive/bearing surface differences but I think it at least keeps the jump to the lands the same. I don't know which has a greater effect: bearing surface differences or jump to the lands...

 

[427Cobra]

Re: inconsistant ogive on 178 AMAX

That's a good question, bearing surface v jump.

 

[SPAK]

Re: inconsistant ogive on 178 AMAX

At 100 yards, .010" variation in jump seemed to change how tight my groups were. Less than .005" I didn't notice too much difference. Doesn't mean it won't show up down range though.

Makes me wonder... if I keep the jump distance to the lands consistent but don't sort by base to ogive, potentially I have some rounds where the bullet is taking up more space in the case than others which I would imagine change pressures slightly. How much difference, I don't know.

On a side note, on a stroke of morbid curiousity I picked up a used juenke machine and the newer amax bullets registered much more consistent and more concentric than older boxes of amax bullets that I have....I haven't had the time to test if it makes a difference or not, but whatever that machine does, the newer amaxes registered way better than the older ones that I had. Not bad, still good bullets per the guidelines in the instruction manual, but definitely not as good as the newer ones. The older ones I had seemed to register on two parts of the meter, almost as if there were two different bullets. Again, don't know if it makes a difference or not, but could possibly be evidence that the bullets might vary in dimension depending what machine they were produced on.

I don't have any other data to support that theory so take that for what it's worth...

 

[jbell]

Re: inconsistant ogive on 178 AMAX

I have been sorting and then seating accordingly to get around this prob. It happens to be my load is 0.005 off the lands and when the "odd size" appears if I seat them like the others they are now jamed 0.005. I choose to keep the same depth in relation to the lands b/c of the potential pressure difference when jammed. I may load some up and run the 2 depths over the chronograph to see the velocity change.

I was just wanting to see if anyone else has seen these length variations.

I do want to point out agan that the bullets were very consistant in length in there respective length groups. These apear to be very good bullets and shoot good for me. Actually this is the first Hornady bullet I have ever had shoot good for me out of a LOT of rifles and many calibers.

 

[SPAK]

Re: inconsistant ogive on 178 AMAX

To answer your question, yes the variation in ogive length isn't isolated. I've found the same thing on the 208s along with others. Like you I've had very good results from them as well regardless of the variations... I'm not convinced it's completely ignorable, but for my needs it doesn't seem to make a difference on my accuracy that I can tell. Although I'm not seating that close to the lands.

Being .005" off the lands I can definitely see your concern with the pressure spikes. My best accuracy with the 208s seem to be between .010"-.020" off the lands.

 

[BCP]

Re: inconsistant ogive on 178 AMAX

I found the same thing with 178 amax's. Doesn't seem to affect accuracy but I don't jam them into the lans either, I make them jump a fair distance.