OK to jump Berger 156 EOL >0.10”?

[KurtB]

6.5-284 Benchmark #2 barrel. Jumping .110, just happens to like it a lot. 156 EOL.

 

[new2mud]

View attachment 165807 I found this on another forum. I have some 147's and some 156 EOL At home that I can measure to get a difference in the base to ogives. Might give you a idea of what you might be looking at if it will help. Like others have said each chamber is going to be different but it's a start

Sure—if you don't mind.

 

[new2mud]

6.5-284 Benchmark #2 barrel. Jumping .110, just happens to like it a lot. 156 EOL.

Nice—thanks for sharing this.

 

[MASH]

Sure—if you don't mind.

Ok so took a sample of ten 156EOL's (because that's all I had left) and ten 147ELDM's.
156EOL. AVG BTO .0785
147ELDM AVG BTO .0771
The Berger's where much more consistent with 5 @ .079 and 5 @ .078
ELDM's ranged from .076 (three) .077(four) .078 (two) .079 (one)

 

[emp1953]

For my .270win I invested some time and money into finding my most accurate load. Let me preface this by saying in most of my center fire rifles I find that .020 set back off the lands is what they seem to favor. Anyway, I found two accuracy nodes with a powder / bullet combo I4350(51.1gr) and Nosler 150gr ABLR (2884 fps). I loaded 50 rounds at both node loadings. I used a seating depth for all 100 rounds where the bullet just touched the lands. I went off to the range with a cleaning kit, and a single stage press with a micrometer seating die. I proceeded to fire 5 shot groups, cleaning the rifle letting it cool, cranking down the depth .001 for each group. Lo and behold it settled on .020 for each node. 3/4" at 200yds out of a SIG 970SHR sporter. By the way the 150gr Partition shoots 1" at 200yds but to a slightly different point of aim.

 

[Deleted member 103481]

Scrap the saami reamer and run a .130 ish freebore

 

[new2mud]

Ok so took a sample of ten 156EOL's (because that's all I had left) and ten 147ELDM's.
156EOL. AVG BTO .0785
147ELDM AVG BTO .0771
The Berger's where much more consistent with 5 @ .079 and 5 @ .078
ELDM's ranged from .076 (three) .077(four) .078 (two) .079 (one)

Cool—thanks for that.

 

[BrentM]

.130 in my prc. Shoot fine

 

[new2mud]

.130 in my prc. Shoot fine

That's the longest I've heard of to date, and really good news. Thanks for sharing this data point.

 

[MASH]

.130 in my prc. Shoot fine

What size action did you build off of ?

 

[Canhunter35]

one thing about barrels and bullets its been my experience that for the most part your barrel either likes the bullet or it doesn't, jump to lands usually won't make or brake a bullets accuracy, in my 300 PRC 230gr Atips touch the lands at 3.845" and I load them at 3.720" with 1/4" accuracy

i agree, I've found accuracy tightens and lessens like velocity nodes as u change ur seating depth. Ex: a 308 seated at the lands then seated at magazine length. And you need to be on ur best shooting to notice the difference

 

[new2mud]

To answer my own question, I finally have gotten out to do some load development in a barrel with .188 freebore, but limited by a SA mag to 2.950" COAL.

For this rifle, loading to 2.950" is a 0.120" jump to the lands.

I tested this week and have gotten several sub-0.5 MOA groups (5-7 shot groups) at 300 yards, using a bipod, so this includes some shooter error. I'm pretty thrilled with this bullet and its tolerance to jump.