Yup ... three outliers in a batch of 50. This visibility is one of the reasons I love my AMP Press. It exposes those outliers, and I can use them for barrel warmers and sight-ins.
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Dedicated mile gun
- Thread starter UKMan
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I'm trying to understand the results that you and I are both getting. You're running a mandrel that is full-diameter for caliber (0.000 interference fit) and still getting seating pressure from 70-100. Seems awful high for that size mandrel. I've tried running a mandrel from the standard 0.306 (-0.002) up to 0.307 (-0.001). With the .306 my pressures were averaging around 140 (also awful high). Going up to a .307 only lowered the pressure to around 140. Going down to a .305 wasn't much different than using a .306 (all AMP annealed, Lapua brass in a 300PRC).
In my 338NM, also Lapua brass, seating pressure is down to around 70 avg using the standard .336 (-0.002 under) mandrel. I can't seem to get the 300PRC seating pressure down, and going to a full-caliber mandrel seems extreme, but your result is what I would expect if I tried it based on my experience with .306, .3065, and .307 mandrels - higher than expected.
Seems to make sense to me, but so do other nonsensical things. LOL
I anneal with an AMP machine, then shrink the neck with a FL bushing die, then expand out to my final size with a mandrel. I pick the bushing die to size slightly smaller than I want, and the mandrel to give me the seating force I'm looking for. At the end of the day, at least for me, seating force is "boss" and I'll use whatever combination of bushing die and mandrel it takes to give me that consistent seating force in the pressure range I'm looking for. I leave the math to the mathematicians ... and just find the right AMP Press-generated seating force and tight range I'm looking for. Hope that makes sense.
I finally got a few rounds through my new 30" Bartlein 338 Edge barrel. Tested loads with Hornady 300gr A-Max and H1000 at 90, 90.5, 91, 91.5, 92. So far, the 92gr load looks promising.
SD - 3.9
ES - 9.7
Avg MV - 2769
group size - .82MOA @ 100yds
Brass is brand new ADG. Looking forward to testing with fire formed brass
Next steps
- Increase H1000 loads to 92.5 and 93 gr. (ultimately i hope to find a good load between 2850&2900)
- Test with Berger 300gr
- Test different bullet seat depths
- Test loads with N565
- Test loads with N570
Also, just received my daughter's 338 Edge from Alamo Precision. Starting to run similar tests and compare performance between her rifle and mine.
SD - 3.9
ES - 9.7
Avg MV - 2769
group size - .82MOA @ 100yds
Brass is brand new ADG. Looking forward to testing with fire formed brass
Next steps
- Increase H1000 loads to 92.5 and 93 gr. (ultimately i hope to find a good load between 2850&2900)
- Test with Berger 300gr
- Test different bullet seat depths
- Test loads with N565
- Test loads with N570
Also, just received my daughter's 338 Edge from Alamo Precision. Starting to run similar tests and compare performance between her rifle and mine.
Leave me alone frick. LOL
I've got a 338 Barrel sitting in my cabinet but I didn't wanna add any projects to my list right now.
completely agree. i make sure to use a neck sizing bushing that gets me to just a little tighter than my target and then use the mandrel to finish the job. Over time i have collected over 20 different bushings for the different calibers i shoot.
one other item not mentioned is the trimming. I have come to learn that case trimming can have a real impact on neck tension. First of all, ensuring the necks are all the same length is critical to consistency. the other part that is often overlooked is dechamfering the inside of the neck opening. Following the neck trimming, i run a brass bore brush on the inside of the neck. When following this process (anneal, size, mandrel, trim, dechamfer, brush) i found the bullet seating to feel noticeably smoother and neck tensions more predictable. I started trimming every time i reload even though that is technically not required because the brass might not grow enough to need a trim. However, sometimes the trim is not to really take anything off but just to clean up the edges.
I have become such a believer in this process that I finally gave in to getting a Henderson case trimmer that trims to length as well as dechamfer on both inside and outside of the neck.
The .338 Edge looks very interesting. Can ditch my .300wm noodle barrel on my Howa. Need to figure out mag/wyatt box for Oryx.
Absolutely. I actually tested the 130/140/144/153.5 Berger loads and they all shot lights out and had great numbers. The only thing I’ve even found that can hang with Berger factory ammo is FGMM, but due to being somewhat close in price, the Berger is the better value due to the Lapua brass, plus the better variety to choose from with different bullets as well. The FGMM loads with 130 and 140 Berger bullets definitely hammer tho.
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