Dedicated mile gun

[rustyinbend]

Yeah, I know, but you have some that are near 100 with a mandrel that’s the same as your bullet diameter, correct?

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.

 

[vh20]

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.

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.

 

[rustyinbend]

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.

 

[GunnyUSMC]

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.