Interesting 208 Amax issue

[jrob300]

I have been reloading on and off for about 35 years and for the most part have relied only on case head to tip COAL as my method of measurement for length.

About a year ago I started loading 208 Amax's in my 300WM and found that they liked to run just off the lands, so I had to learn a slightly different technique, but with the proper tools, it's really no more complicated.

Until yesterday...

I had several hundred Amax's I bought about a year ago and as that supply has run low, I purchased some more just recently.

I was loading for the shoot at Augustis' Ranch this weekend and ran out of the old bullets. So I compared base to ogive, weight and base to tip measurements between the lots. They were virtually identical, so I just kept loading.

Later, for a reason I don't even remember, I picked up one of the last rounds I loaded and measured the case head to ogive. It was .010 long. Huh?

I remember hearing about rounds "growing" overnight but that was in a compressed load. So without giving it a lot of thought, I reset my Redding Competition seater and reseated them .010" deeper. Suddenly I started to get rounds that were .010" too short. What?

Clearly something had changed in my process. Then I remembered the lot change of bullets. But I checked them and they were identical. Hmmm...

I pondered this for a bit and this is what I concluded. We determine ogive position with a Stoney Point gauge (or similar) and use that as the reference to set our COAL off the lands. But the seater does NOT reference off the ogive. It bears up near the tip. So, if there is any inconsistency or variation in the shape of the bullet where the seater bears, there will be a change in case head to ogive length.

Logically this means my newer Amax's were *slightly* narrower at the tip and could slip .010" further into the seater.

So, even though base to ogive and base to tip were the same, they were NOT the same shape. I'm assuming this would affect BC also. BTW it is NOT apparent by looking at them.

Have any of you run into this before?

Just wanted to make others aware of this possibility.

I will separate my loads by lot now no matter what.

John

 

[bohem]

Re: Interesting 208 Amax issue

Yes, I've seen this. My 30+ year old RCBS comp micrometer seater bears on the ogive of the bullet about 50% of the way down the length of the ogive and seems to keep things pretty reasonable.

I measured some ammo with the comparator and the bullets came from 2 different lots. They all fell within 0.001" on either side of the set point.

My new "ogive" seater from RCBS for the 223 bears about 1/4 ogive down from the tip and the 75 Amax's actually bear on the tip a little bit. This is far less repeatable and I had the chase down the same issue that you described.

 

[jrob300]

Re: Interesting 208 Amax issue

I wonder if Hornady is aware that they have this much variability in their process? This *has* to affect BC.

I don't check every round (usually at setup, then the first few, one in the middle and the last), so it's possible that round to round is very close, but lot to lot has more variation.

I'm going to give them a call today.

John

 

[jrob300]

Re: Interesting 208 Amax issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">Yes, I've seen this. My 30+ year old RCBS comp micrometer seater bears on the ogive of the bullet about 50% of the way down the length of the ogive and seems to keep things pretty reasonable.</div></div>

This seems like the ONLY way to guarantee consistent ogive positioning. I have the micrometer head on my Redding also. I'm *really* surprised that these high dollar seaters are not designed more intelligently.

Do you know of any of the current seaters that bear on the ogive?

John

 

[NRF]

Re: Interesting 208 Amax issue

I don't know for sure what the Forster comp. die does, but I measure every round and haven't seen more than a .002+/- difference but these bullets are still all the same lot, could be the bullets and not the die??

 

[jrob300]

Re: Interesting 208 Amax issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NF41780</div><div class="ubbcode-body">I don't know for sure what the Forster comp. die does, but I measure every round and haven't seen more than a .002+/- difference but these bullets are still all the same lot, could be the bullets and not the die?? </div></div>

I went back and checked all 150 rds. I loaded and I'm getting less that +-.002" myself. So rd. to rd. is not the issue and seems to be restricted to across-lot variation.

I talked the the tech rep at Hornady and he said it was not a problem that they were aware of, but was a distinct possibility, because they don't check every point of the bullet, and every seater die bears on a different area.

Hence the need for a seater that bears in the same place the measurement is taken from, which ideally would be where the bullet meets the lands.

John

 

[bohem]

Re: Interesting 208 Amax issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NF41780</div><div class="ubbcode-body">I don't know for sure what the Forster comp. die does, but I measure every round and haven't seen more than a .002+/- difference but these bullets are still all the same lot, could be the bullets and not the die?? </div></div>

I went back and checked all 150 rds. I loaded and I'm getting less that +-.002" myself. So rd. to rd. is not the issue and seems to be restricted to across-lot variation.
</div></div>

Cross lot contamination is the culprit that I've seen. There was thread on here not long ago about the same problem with some 168 SMK's in 30 cal that had 0.020" of base to ogive variation in the same box.

Turns out that Sierra has 8 machines churning out 168's and dumping them all into one box, the variation in 8 different machines all adjusted to 8 different points threw off the consistency. The OP on that thread ended up throwing the bullets out IIRC.

Thus far, I haven't seen that from Hornady or Berger. Lot to lot variances don't bother me as long as I'm not trying to put 2 lots together without checking them. When this happens I just check the ogive length to verify on 3 rounds of the new lot and then push forward.

I do not know of any of the newer seating dies that will contact as far down the ogive as the RCBS seater I have. I bought it Nth hand and it's older than I am, but it works really nicely.

 

[jrob300]

Re: Interesting 208 Amax issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">Lot to lot variances don't bother me as long as I'm not trying to put 2 lots together without checking them. When this happens I just check the ogive length to verify on 3 rounds of the new lot and then push forward.</div></div>

This is the mistake I made. Having checked the bullets themselves, I *thought* I was safe. But I KNOW the best test is always the finished product and that I did not check until it was way late.

Now I know and I hope others can learn from my mistake.

My biggest concern at this point is that although they are all seated correctly now, somewhere in that lot change (which I lost track of)is a difference in BC that's going to bite me just at the wrong time.

Hopefully it's so small that it will be lost in the noise, or it will show up on the plate and I can make an elev. correction on the fly.

John

 

[Bigwheels]

Re: Interesting 208 Amax issue

I have seen the same thing, & even have several boxes that had different lots mixed together. Most are only .001"-.003" difference, but I have seen some that were off by .009". I have not seen any noticeable change in trajectory with the different lot's tho, so I think you are GTG anyway.

 

[hypertex]

Re: Interesting 208 Amax issue

Don't know if this is an option but Hornady makes a seater specifically for the 208 AMAX

 

[SPAK]

Re: Interesting 208 Amax issue

I'm still pretty new to this game, but I seat my 208's about .010 longer than my goal oal to ogive. Measure with the comparator and then make the necessary adjustment on my micrometer seater to get to my goal oal. Definitely slows things down a bit, but my oal on all my loads are within .001". I don't know if it's necessary or not, but when I didn't check each load I found variances up to .005". I don't have enough experience to tell me whether or not .005" in seating variation will make that much difference downrange or not, but in my strive for the best and most consistent ammo, I am happy with my process.

I would imagine, perhaps differences in neck tension case to case can change your seating depth variation much like a compressed load would. my limited .02

 

[bohem]

Re: Interesting 208 Amax issue

Frog-

If you get an ogive seating stem for your die you can cut that process back to just setting the die initially and running with it. The only time I recheck the length is when I change from lot to lot of the same bullet or when I switch bullets (obviously).

The tip seaters are also very tough on match grade pills, especially the polymer tipped ones like the Amax series.

I'm currently working out loads for a new 6.5-06 that I chambered on Tuesday. My 30 cal ogive seater kept the base to ogive lengths +/- 0.001" on the 140 Amax when I was setting up a ladder test.

 

[SPAK]

Re: Interesting 208 Amax issue

I actually do use a vld seater stem with my redding comp die, but I still find the variation even within the same lot. (is that different than the ogive seating stem that you are reffering to?)

I don't sort my bullets, that might be part of it. Although, I will say that the majority of the time, my final seating depth setting on my micrometer is the same or within .003".

If my neck tension is different (I interpret that as difference in seating pressure) the chance of variation is usually greater).

 

[doc76251]

Re: Interesting 208 Amax issue

I'm partial to drilling a "cavity" into any seater stem that I find bearing against the bullet tip. I then break the edges with a small Cratex polishing bit.

This allows the seater stem to contact the bullet farther down the length of the boolet and not crush or deform the tip. I found this very handy when loading 210 Berger VLD's but it applies to all boolets. The closer the cavity that you create is to the ogive diameter (NOT LARGER) the more consistent your seating for ogive measurement gets.

I also am partial to "pre-seating" the bullets to a fixed length to get them closed up. Then I measure each one and adjust the die to the final length, returning the die to "zero" after each round. Slow but very consistent and it works even if your changing boolet types / lots.

Cheers,

Doc

 

[Tribe]

Re: Interesting 208 Amax issue

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hypertex</div><div class="ubbcode-body">Don't know if this is an option but Hornady makes a seater specifically for the 208 AMAX </div></div>
Hypertex.... do you have experience with "this"?

 

[laserrifle]

Re: Interesting 208 Amax issue

I have a recently purchased a lot of 500 and they were so inconsistent in base to ogive that I had to sort the whole batch to make them shoot. Loaded the first 50 of that lot and was having 3x the normal vertical spread of that load with a previous lot of 208s, everything else was the same so I started measuring and found .020" in variation and 2 out of the 500 had plastic tips that were not even completely formed. Just my experience, and as the saying goes, "you get what you pay for".
AMAXs are cheaper than the competition for a reason.