50gr Berger Testing

[BabaOriley]

I just loaded up 60 cartridges with the 50gr Berger HP for testing in a 23" 1:10 twist barrel. I have read all over the place that 1:9 is required for the 50's but want to find out for myself.

Note: Because I'm using an AR-15, I loaded ALL of these to 2.247" COAL base to tip so they fit in the magazine. I can measure with a comparator if someone wants me to, but I was really only measuring to see none wenbt over 2.247". Many measured around 2.244". The length Hodgdon shows in their online data for this bullet is 2.300". Someone please let me know if you think I'm going to blow my face off because I'm seating these Looooong bullets too deep. If I have to load them at or over 2.300" and load them one at a time, that may be fine with me. I just figured I might as well do the testing at a length that I can shoot them semi-auto.

Here's the charges I loaded tonight:

Benchmark 22.5gr recommended starting load - 24.0gr max load
(5)@22.8gr
(5)@23.1gr
(5)@23.4gr
(5)@23.7gr

Varget 24.0gr recommended starting load - 26.0gr max load
(5)@24.7gr
(5)@25.0gr
(5)@25.3gr
(5)@25.6gr

H322 22.0gr recommended starting load - 23.5gr max load
(5)@22.2gr
(5)@22.5gr
(5)@22.8gr
(5)@23.1gr

My plan is to shoot them watching for pressure signs and keyholes at 100 yards. If they shoot, I'll take the most accurate and move out to 200, 300 etc...

Any predictions? Will they work? Which one will be the most accurate? I would like to try H4895 with these too but don't have any right now. If they all keyhole, I may have some ammo for someone with a 1:9 twist barrel. Since I want to try these thinking they may work well at longer ranges on coyotes, I think I'll do this testing at coyote hunting temps sometime in the next coule weeks when it's about 5-10F outside. I'll post the results here!

[scootertrash]

Using QuickLoad and the info you supplied, all three of your max loads appear to be safe pressure wise. Looks like you did your homework well!

FWIW, I use the 50 grain Bergers in a ten twist 20PPC. They are pushed by Varget and it shoots incredibly well.

Mike

[BabaOriley]

Thanks Mike!

I was hoping for some assurance that staying back from the max load a bit would allow loading them .053 shorter than Hodgdon's load data was derived from. Is there some formula on what is absolutely too deep to seat a bullet, like the ignition force would be pushing too much on the sides of the tail than pushing it out the barrel? I could imagine you could run into a problem on many VLD bullets trying to fit them in an AR-15 magazine. This is my first run-in with that issue. Like I said, I'll try them single shot if necessary to be safe. I hope some more chime in on this.

[jo191145]

My bets on the Varget. Best burn rate of the three.
If they work at all of course. An on the edge bullet does not need to keyhole to be unstable. Lousy accuracy usually comes first.
I wish you the best and hope they do work for you.

As for how deep they're seated.
I have seated LARGE (208 A-Max) 308 bullets with the shank of the bullet intruding into the case and found good accuracy. Usually this is not reccommended but it worked.
Doughnuts can become a problem but can be avoided by partial necksizing as long as its not a tightneck chamber.
Pressures might spike a little sooner but that would'nt/did'nt stop me from trying.

[Bunnybuster]

BabaOriley: The pressure on the sides of the bullet have no bearing on the force pushing it out of the barrel.

Picture a cross section length wise through the bullet, case and chamber, with little arrows representing the pressure pushing on the bullet, and out on the case. The pressure from the sides of the bullet balance out to zero. The pressure on the back of the bullet is unbalanced, and pushes the bullet out.

Where you run into problems, is that the further in you seat the bullet, the less case capacity you have. The lowered case capacity can result in higher than expected pressures.

You might want to seat a bullet into an unprimed case, and then use a syringe to fill the case with water, weighing the case before and after you fill it to determine the water volume.

Scootertrash could probably run it through his software and see what pressure you should expect with the reduced case volume.

[BabaOriley]

It was 42F here yesterday, and I managed to get to the range for a couple hours with these loads. It was a pretty hasty shooting session because I had a bunch of other things to get done yesterday. I can't attest to the accuracy of any of these loads, because I couldn't find my heavy front bag rest, and ended up using an MTM predator rest (plastic) that doesn't fit my AR very well, so it took a while to settle in to a comfortable shooting position. I also got to the range and couldn't find my stapler, so ended up using some shoot-n-c targets left up by someone else. I had to take my knife and scrape off some of the coating on the old target to make a bunch of new 3/4" bullseyes. No measurements, and I didn't bring the chronograph along, but the 25.3gr Varget load seemed to give me the tightest looking group. Good guess jo! I have no doubt that 12 of these 16 loads would shoot better sub moa if I had used a better rest. My final excuse for yesterday's poor shooting is I had a very difficult time even seeing 100 yards through the very thick fog. I would find the bull I wanted to shoot at, then put my crosshairs on it, but shapes were so blurry I had a hard time noticing if the crosshairs were moving. Sometimes it felt like I was aiming for a general vicinity of the bull I wanted. I was surprised how tight some of the groups turned out.

The main thing I wanted to verify yesterday was that the 50gr Berger will shoot in my rifle, and I'm pretty sure I accomplished that. I shot all 60 rounds in the order you see in the first post above, NO KEYHOLES. I think the next step for me is to take that 25.3gr Varget, and load up some on either side of it, then move out to 200 and 300+ yards to see if the stability and accuracy remains.

It's too early to tell at only 100 yards if these bullets were truly stable, but it's looking good so far!

[jo191145]

Welcome to the crappy conditions shooting club I think just about everyone has been suffering from that lately. I haven't pulled a trigger since sometime in Nov. Even though the forcast was calling for rain today I considered making some noise. Lots of fog from warm temps,rain and melting snow. Seeing as I needed to shoot an Audette at 200yds I decided to wait.

Good to hear the big Bergs worked. It makes good business sense Berger would hedge a bit on the twist rate.
I still wonder why most factory tubes do not come in 11 twist to "hedge" the 40's.

Sounds to me you had some barrel heat mirage going today. I'm no stranger to that myself.
FWIW
I just picked up a small battery operated personal fan from a WalMart. I think it was $3.98 and is powered by two D cell batteries. I haven't had the chance to try it yet but it should do the trick. How long it will last is another question entirely.
For the money its a cheap investment for anyone who has contended with barrel heat mirage. I've seen competitive shooters using them so why not. Just do not let the draft blow across the muzzle and your all set.