• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

First attempt to develop a load for the Berger 85.5 with Varget - updated with more testing

Generally speaking, the reasoning is to stay out of the region where donuts may start forming - where the (relatively) thicker brass in the shoulder may flow into the neck area over time as the case gets sized (repeatedly).
 
Not sure if I'm understanding the question correctly here. What Monte is referring to is having the boattail/bearing surface junction too far down in the neck so it contacts or rides over the donut during seating. That is actually the reason to keep the boattail/bearing surface junction at least 1/4 to as much as halfway up the neck, not out of it; i.e. keep it well above above the region where donuts form.

That is a very different thing than not allowing the boattail/gearing surface junction to rise into the neck (i.e. keeping it below the neck). Sure - it's possible to do that, in fact, I've been forced to do exactly that with a .223 Rem that had zero freebore in order to load up the long 80.5 Fullbore bullet. However, it is not ideal, and not normally necessary when single-feeding rounds. When using 1.5 to 2 thousandths neck tension (interference fit), having ~ one half of the total neck length occupied by bullet bearing surface is more than sufficient grip on the bullet. In fact, you can get away with even less, although I would prefer to have the reamer designed to give me ~1/2 to 3/4 the neck length occupied by bearing surface between the shortest and longest (lightest/heaviest) bullets I intend to use with that particular rifle, and still keep the boattail/bearing surface junction well above the neck/shoulder junction. Positioning bullets in this region in the case neck maximizes effective case volume, minimizes donut issues, and usually allows seating bullets into/touching/off of the lands as needed.
 
Last edited:
Generally speaking, the reasoning is to stay out of the region where donuts may start forming - where the (relatively) thicker brass in the shoulder may flow into the neck area over time as the case gets sized (repeatedly).
I run a sizing button in my 223 sizer. Doesn’t that eliminate a donut by pushing it out to the outside. Then i am not limited to any amount above or below the neck/shoulder withe the boat tail??

my own experiments for runout with a 223 because its neck is shorter than 1 caliber is to always have a full bearing surface in the neck. I don’t run jammed load lengths.

David
 
We had some decent weather this morning so I finished my 100 yard testing for a Palma load with the Berger 85.5 grain bullet. The rifle is a Barnard Model P with an ISSF/.169 freebore chamber, 30 in. long 7 twist Kreiger std. Palma barrel.
I tested five (5) groups starting from 25.2 grains N140 to 25.5 grains in .1 grain increments. I was using Winchester brass, CCI450 primers, and jumping the bullet .015. After testing up to 25.0 grains of powder I switched from the CCI-BR primer to the CCI450 thinking they would resist the higher pressure. It turns out both have the same cup thickness according to information found on this forum and I got vertical stringing in my groups that I had not seen prior to the switch. The primers were flattened but still rounded on the edges. The one round in the last group giving 2961 was a little hesitant to extract but otherwise there were no signs of excessive pressure. There may be other contributors to the stringing as I am a sling shooter and my bench technique could be improved. At 25.5 grains the load was slightly compressed. The best results for my application are as follows:

25.4 grains N140
Avg.: 2937 Extreme Spread: 41 FPS
High: 2953 Std. deviation: 16.7
Lo: 2912
5 shots
The group was almost completely vertical measuring about 1/2 inch tall

25.5 grains N140
Avg.: 2942 Extreme Spread: 29 FPS
High: 2961 Std. deviation: 11.4
Lo: 2932
5 shots
This group was rounder but noticeably larger.

The next step is to test ten shot strings at 500 yds. and later at LR. The usual words of caution apply.
Tom Alves
 
Last edited:
I was hoping to see some H4895 results.
Barrel is a Preferred Barrel Blanks 27" Varmint 900 contour mated to a Howa SA.
My testing for powders included Varget, RL15, N150 and H4895. Due to range restrictions it has been a slow drawn out process.
H4895 gave me the best velocities, I tested 23.0 - 25.2; .2 grain implements.
Found a node between 24.4 and 24.8 settled on 24.7, AVG 2853
.015 OTL gave me ~2.530 COAL
25.0 and .2 hit the 2900 mark, showing slight pressure, cratered primer but no flattening.
No sticky bolt ext. Could possibly go higher but I am happy in the 2850 range.
My initial gross seating depth showed .060 off to be the best with .015 close behind; .015 chosen for powder.
 
I was hoping to see some H4895 results.
Barrel is a Preferred Barrel Blanks 27" Varmint 900 contour mated to a Howa SA.
My testing for powders included Varget, RL15, N150 and H4895. Due to range restrictions it has been a slow drawn out process.
H4895 gave me the best velocities, I tested 23.0 - 25.2; .2 grain implements.
Found a node between 24.4 and 24.8 settled on 24.7, AVG 2853
.015 OTL gave me ~2.530 COAL
25.0 and .2 hit the 2900 mark, showing slight pressure, cratered primer but no flattening.
No sticky bolt ext. Could possibly go higher but I am happy in the 2850 range.
My initial gross seating depth showed .060 off to be the best with .015 close behind; .015 chosen for powder.


I have another thread about my h4895 testing with the 85.5. Bottom line for me was that yes h4895 did give me more velocity than varget but with very small nodes. With both varget and h4895 the 85.5’s seem to really tolerate jump.

David
 
I have another thread about my h4895 testing with the 85.5. Bottom line for me was that yes h4895 did give me more velocity than varget but with very small nodes. With both varget and h4895 the 85.5’s seem to really tolerate jump.

David

Saw that after I posted.
My best groups at 100 yards were with the N150 but .... couldn't get enough powder in the case.
 
Saw that after I posted.
My best groups at 100 yards were with the N150 but .... couldn't get enough powder in the case.
Sometimes it is as important to know what not to use as it is what to use. Keeps you from chasing your tail

David
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
165,555
Messages
2,198,169
Members
78,961
Latest member
Nicklm
Back
Top