140gr Bergers and LeveRevolution

[Allen]

I finally got a chance to pickup some powder this weekend. Since I couldn't get any CFE I decided to get some LeveRevolution instead. The bullets were 140 gr Berger's VLD hunting bullets. I did a ladder test from 28.1-30.8 in .3gr increments, seated to 2.295" (mag length since the were at the lands at 2.355") The hottest load was 2410 fps. I was really disappointed in the accuracy. At 200 yards I wasn't even hitting paper so I had to move into 100 where the hits were all over the paper in no particular group or order. I didn't really noticed any real pressure signs even at the 30.8 load. I was kinda wondering if the 1:9 twist is too slow for the 140's. Also, how much is too much when it comes to compressed loads? Will the bullet stop or will you just hear it crush? The last 3-4 loads I could definitely hear the powder crunching.

I've got some 123 Nosler C's loaded up with this powder so hopefully they shoot a bit better.

[Drifter]

I was kinda wondering if the 1:9 twist is too slow for the 140's.

That would be my guess.

Berger website indicates 1:8" twist or faster for that bullet:

http://buybergerbullets.3dcartstores.com/65mm-140-Grain-Match-VLD-Hunting_p_79.html

[XcountryRider]

Also need a special die to load.

[Allen]

Also need a special die to load.

???? Can you explain?

[XcountryRider]

[Bwild97]

I finally got a chance to pickup some powder this weekend. Since I couldn't get any CFE I decided to get some LeveRevolution instead. The bullets were 140 gr Berger's VLD hunting bullets. I did a ladder test from 28.1-30.8 in .3gr increments, seated to 2.295" (mag length since the were at the lands at 2.355") The hottest load was 2410 fps. I was really disappointed in the accuracy. At 200 yards I wasn't even hitting paper so I had to move into 100 where the hits were all over the paper in no particular group or order. I didn't really noticed any real pressure signs even at the 30.8 load. I was kinda wondering if the 1:9 twist is too slow for the 140's. Also, how much is too much when it comes to compressed loads? Will the bullet stop or will you just hear it crush? The last 3-4 loads I could definitely hear the powder crunching.

I've got some 123 Nosler C's loaded up with this powder so hopefully they shoot a bit better.

A twist rate that is too slow will not produce horrid groups, it will produce keyholes in paper targets. So will an over stabilized projectile.

Here is a very good Twist calculator. Twist

This is what an under/over stabilized projectile looks like on paper


At the time of your testing, did you have a muzzle device attached to the end of your barrel? If so, remove it and try again.

Also, how much is too much when it comes to compressed loads? Will the bullet stop or will you just hear it crush? The last 3-4 loads I could definitely hear the powder crunching.

This is what it looks like when powder will not compress any further.

[rasp65]

I have had primers push out on cases that had loose primer pockets.

[rasp65]

You could also measure the amount of powder space with a seated bullet using this: http://www.handloads.com/files/powleycomputer.zip Then Go to the Lee Reloading site http://leeprecision.com/cgi-data/instruct/VMD.pdf . Take the water capacity of powder chamber divide by 7000 and divide that by .002205 that will give you case volume in cc. Take the VMD from the Lee chart for the powder you are using and multiply it by the weight of your charge that will give you the volume of your charge in cc. Divide the charge volume by the case volume and multiply by 100 will give you the charge density. You could even add the formulas to the spread sheet and make the info automatic. Studying AA data the highest density I found was about 107 for 2520.

[Allen]

Thanks allot Bwild. I have a brake on the end, but it shot fine with other bullets. Do you think that could cause that much of a problem. I did take my Hornady die and put one of the bullets in the seater and it did touch on the tip before the ogive, but not by much. I might stick the seater in the drill press and take off a 1/8" off of it.

[cory]

Thanks allot Bwild. I have a brake on the end, but it shot fine with other bullets. Do you think that could cause that much of a problem. I did take my Hornady die and put one of the bullets in the seater and it did touch on the tip before the ogive, but not by much. I might stick the seater in the drill press and take off a 1/8" off of it.

I don't disagree with bwild. If the bullet is contacting your muzzle device in the slightest it'd cause problems. I doubt that's the problem, but why not remove a variable.

Berger talks about the problem you're describing in their video. Personally I'd buy a single full length seating die for VLDs.

I wouldn't put your die in the press. I think you risk more problems doing that. Scratching up the inside of the die, cracking the die, etc.. Even if there is no problem from the drilling you're going to need to take a dremel or similiar tool with very fine sand to smooth it out, then you'll need to take a soft tool and polish that.

By the time you get that done you could have a specialized die sitting at your door step.

It's been a while so I may be remembering this wrong, but I think I've read that the VLDs should contact the LANDS when chambered. I think I read bwaites saying that also.

I apologize if my recollection is off. I'd search VLDs.

[Bwild97]

If you have a set of Hornady dies you can make custom seating stems. Extra stems cost about $13.00 and midway usually has them in stock. I buy the Amax seating stems because they have a longer ogive in them for the VLD type projectiles.

To customize the stem I use a method described by Stokesrj, where you remove the stem from the die.

You may need to remove the tiny little nub in the middle of the stem head, be very care to not damage the flat surface of the stem head, this nub is more of an annoyance than anything,

on a flat surface the stem will sit at a cant and you need it to sit straight. Place the stem upside down so that you are looking down into the ogive.

Mix up some 20 min. Epoxy (a very small amount unless you have several stems to customize). Coat the ogive of the projectile you are going to customize for with case lube, Bow string wax, beeswax, something to act as a release agent.

Fill the stem with the Epoxy you mixed, and place the projectile in the stem, let it stand overnight, in the morning you will have a custom seating stem.

[bwaites]

A twist rate that is too slow will not produce horrid groups, it will produce keyholes in paper targets. So will an over stabilized projectile.

Here is a very good Twist calculator. Twist

This is what an under/over stabilized projectile looks like on paper

I agree with almost everything Bwild says, but overstabilization appears to be an urban legend. Spinning a bullet faster does not cause keyholing.

According to Bryan Litz there are really only two issues with spin: Increased dispersion and bullet fragility. If the bullet comes apart, (unlikely at Grendel velocities unless there is a barrel issue) all bets are off.

Dispersion is an issue if you spin the bullet so fast that the Sg is over 2.0. Bullets GENERALLY aren't accurate when you do that, but it doesn't cause keyholing.

There is some leeway with spin rates, but Bill Alexander worked really hard to come up with the recommended twists for the Grendel. That's why long barrels have a different twist than the shorter barrels. They fired LOTS of bullets with twists from 6 up to 11 or so trying to determine the optimums.

[richie301]

The elephant in the room is that a 1-9 twist barrel cannot stabilize a 6.5mm 140 berger bullet that is 1.421 inches long. Regardless of what Bwild's worst case scenario of keywhole targets shows. You may not see the extreme yaw that his targets illustrate but the large group sizes are a result of that destabilization. If you need to shoot these bullets get a 1-8 twist barrel. You can blame bad groups on many things but get the twist correct first.

[Allen]

I know that I can finesse the seats to make it work. The hornady die doesn't have a tapered hole, just a straight blind hole. If I make it a bit deeper (just a few thousandths) it should work just fine. I need to take my brake off anyway cause I think its upside down so I'll try that too. Thanks for all the responses.