Preping to Play with 300gr Berger Hybrids

[royinidaho]

The Berger 338 Hybrids came from 3rd Gen the other day an all I've done is oogle at them.

They look to have spent a bunch of time in the polisher. Don't don't know if that's good or bad. Though I don't like to see jackets any thinner than they need to be.

Cosmetically they win the beauty contest with the SMK. However, from the many SMKs that have penetrated my 8" very fine sand backstop the Bergers will have perform pretty well to keep up. If the sand contains any moisture at all, the second shot out of the RUM always completes penetration. I have to wack the backstop with a sledge hammer between shots to keep bullets contained. (I've since piled lava rocks behind the backstop to contain things)

The Hybrids are definitely long. About 0.090" longer than the SMK with a bearing surface that is about 0.009 shorter. Diameter of the Hybrid is slightly less than that of the SMK.

When seating both bullets on the lands (for the first setting for the Hybrids) the cartridge base to ogive measurement is an average of 3.052 for the SMK and 3.125 for the Hybrid. I'm a little confused by the difference in these numbers as I let the chamber seat both bullets in a dummy case.

The attached pic shows the Bergers produce a longer overall cartridge length. The appearance is exaggerated a bit by the angle of the camera and placement of the SMKs in the next row back of the loading block. The overall length of the Hybrids is 3.9 inches (just barely long enough to prevent fully extracting a loaded round with out releasing the bolt. The SMKs overall length is is 3.8" a full 0.10" shorter.

As the bearing surface and diameter of the Hybrid is a bit smaller than that of the SMK I figure I'm safe in using the powder charge that has been developed for the SMK.

I'll shoot these six shots tomorrow in a round robin fashion and see what happens.

 

[jmden]

It'll be very interesting to see how these compare in your sand penetration tests...

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Roy--haven't heard that you received your 375AM yet...? Figured we'd all know if you did! Kirby says my 338AX will be ready today or tomorrow and then he'll get out for range testing...it's been nearly a year and a half since I started gathering parts for this thing...

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On another note (don't want to hijack here, Roy) but, has anybody used LoadBase and gone between using velocity banded G1 and G7 data and compared the drop output of the program vs. actual drop at 1k+, for instance...??

 

[winmag]

The attached pic shows the Bergers produce a longer overall cartridge length.

Wheres the attached pic Roy? Sounds like your gonna have fun. Cant wait to see the results.
Does this mean your putting the testing of your''woof-whackers'' on hold?

 

[trueblue]

pics ?

 

[royinidaho]

oops!! Senior moment...... Pic is there .......now

jmden,

Kirby has had all the parts for quite awhile maybe a year. Including scope mounts, scope, trigger, A-5, action, barrel and level. I'm just standing by with aggressive patience.

It should be soon. I'm going to email him to see how long of a hard case is needed to fit that sucker....

 

[winmag]

Nice pic Roy. They both look neat, now its time to see if they shoot as good as they look. Awaiting results.

 

[royinidaho]

Darned rain. Wanted to get some shots in today. No such luck. Rain!! Every time I started dragging stuff to the range behind the house it began to rain like a cow peeing on a flat rock!!

So, helped son on the theater room remodel. Gonna watch LRH vids between sun shine moments.

 

[winmag]

Darned rain. Wanted to get some shots in today. No such luck. Rain!! Every time I started dragging stuff to the range behind the house it began to rain like a cow peeing on a flat rock!!

So, helped son on the theater room remodel. Gonna watch LRH vids between sun shine moments.

I here that, Spring time in the high desert sucks! You get all four seasons 3 times a day

 

[royinidaho]

Preliminary results of the test. Interesting comparison but much too early to make a statement one way or another.

Loaded 3 shots w/US-839, 101 gr and SMKs as the check load. This is my goto load. Velocity average was 2337 with an ES of +/- 1 for 3 - 3 shot groups last year.

I was expecting 2735 fps w/ES of 1 and 0.6 to 0.5 MOA. Average velocity was 2773 and 0.75 MOA @ 200 yds and an ES of 26. Must have been different daylight conditions that accounted for the increased 40 FPS. No understood reason for the increased ES.

Loaded 3 with the same 101 grain US-869 with the ogive "almost" touching the rifling. Average velocity was 2716. ES = 18 and a group size of 2.65 MOA. Shot a real nice but large triangle.

Loaded 3 more with 101 gr US-869 and jumped them 0.040" more that the first three. Average velocity was 2735. ES = 47. Group size = 2.23 MOA. Again a nice large triangle centered about 1/2 MOA to the right.

The center of each group was about 1.5 MOA high. About correct @ 200 for a 300 yd zero.


The extra 0.040' jump made very little difference except for shifting the POI to the right.

I did some pondering and figured that 2 things could be incorrect.

1. The bullet may not like US-869 and,
2. The Hybrid may not act like the typical Berger bullet design.

So, as is typical for me, I changed two variables instead of one for the next three shots.

1. Switched to 90.5 gr of Retumbo and
2. Seated the Hybrids 0.003" longer than those just touching the rifling. Just touching means no marks are shown on the bullet when the live round is extracted.

Very slight, though noticeable if attention is paid, bolt close resistance could be felt and a very small mark existed when the 0.003" longer loads were chambered and extracted.

The shots with 90.5 of Retumbo averaged 2772 (1 FPS less than the SMK US-869 load) ES = 66 (not so good) Group was spot on windage wise, 1.5 MOA high as were the other Hybrid groups with a size of 0.875 MOA.

Here's what will happen Monday if it isn't raining.

1. Load the Hybrids 0.003' more for a total of 0.006" increase over the "just touching" loads with 90.5 of Retumbo. (To see if the group shrinks or enlarges)
2. If the group shrinks, load 101 gr US-869 to see if the bullet has a thing against the powder
3. If the group gets bigger then drop back to the 0.003" longer than the "just touching" loads to validate today's results.
4. If today's results are not matched with the above tests then, tweek with powder charge weights a bit. (I'm plenty below 'my' max but not much.)

There should be a definite indication of where things are by then.

B1-3: Hybrids seated "just touching" w/101gr US-869
B4-6: Hybrids seated 0.040 back w/101gr US-869
B7-9: Hybrids seated 0.003" longer than B1-3, w/90.5gr Retumbo.

All shots 200 yds
Prone/bipod/rear bags
The target is so blotchy due to hanging in the rain for a day
​

 

[jmden]

Well...huh...interesting, Roy. Thanks for sharing your info. Be very curious to see what ends up working for you. Keep us posted.

Thanks again,

Jon

 

[royinidaho]

Well...huh...interesting, Roy. Thanks for sharing your info. Be very curious to see what ends up working for you. Keep us posted.

Thanks again,

Jon

I just posted some questions to canyonman1 regarding what seating length with respect to rifling he's using on his Edge. Never having shot Berger's I would expect that with the Hybrids that they wouldn't be finicky about seating depth. Hmmmm.

Happy to hear that your AX is nearing completion. I have no idea where my 375 is in the queue. It was supposed to be in the 'next batch' a couple of months ago.

 

[royinidaho]

Just got answers to my questions.

Wow! Amazing to me!

I may just due a ladder test using seating depth as the variable instead of powder charge.

A 0.115 jump seems huge and may be due to the throat dimensions. My chamber is Remington factory and seems short throated.

 

[royinidaho]

Dumb me!

I just took another note of Eric's article on seating the Berger's.

For some reason I assumed the Hybrids would differ from the VLDs and proceeded to not pay attention to the article.

I'll do what he said except 3 shots vs 6 per seating length.

 

[jmden]

Berger Bulletin

Litz has made some significant changes to the bullet BC first published and found some other interesting things as well. Good on Berger for being so honest and I hope they get things worked out soon.