I decided to work with my 260 Encore a little more today. Mainly sighting in my new Weaver Extreme Classic 2.5-10 Scope. I wanted to try more loads out in it also. I found a pretty good looking load on the Hodgdon Reloading Guide site using Benchmark with the 107 SMK bullet. I was chronographing loads when I touched off my first shot that was .5 under the maximum listed. My reading was 3122 fps from a handgun barrel.

When I went to open the gun it did not want to eject the round. When it did come out the primer fell out of the case. Way to Hot.
I am not sure that this can of powder is not the problem instead of the listed load data. Every time that I have tried to use this can of Benchmark over the years it has seemed to be way warmer than I thought it should have been. I will pull the other 14 rounds down.

Now I will need to decide if I want to drop the load way back and work back up with this can of Benchmark like I should have done to start with, or just go back to H4895.


Bob R

That's one hot load.

Do you have any Benchmark from a different batch to compare it against? It might be interesting to see if they had an off batch.

Chance I do not. I have had this one pound jug for over 10 years. I have thought it might work in a couple applications over the years, and always abandoned using it. I am wondering that if I drop the load back to a point I feel good to start testing it again that I might have way too much air space in the case.

I found this post on 24 Hour Camp Fire from 2009:

{Any of you guys ever try Benchmark in the 260 Rem? Hodgdon's data shows that 40 grains is tops with a 120 grain and 43.5 is tops with the 95 grain Vmax with a velocity of 3391 fps.

I thought I would give it a try. I dropped down to 40 grains with a 100 grain ballistic tip and it blew the primer clean out of the case and stuck the brass to the bolt face!

I tried again yesterday with the 120s and 36.5 grains made the brass flow into the ejector hole!

I don't know if I have a fast lot or if it is bad data. They actually show a higher powder charge with BM than with Varget for the same bullet!}



Looks like I am not the only one to have problems with this load data. This article had some Quick Load calculations that came up with Way to much pressure with the loads listed.

Bob R

Interesting development. Looks like the suggestion would be to drop back a good ways before starting again. I wonder if a google search of your lot # of powder would turn up any recall notices of other posts about hot loads.

It's nice to have multiple tools to double check things when reloading. Published data from manuals, factory websites with data, a chronograph, Quickload and factory ammo to cross check your results and expectations.

Best of luck, let us know how it works out.

Bob I am surprised that you started as high as you did with Benchmark. 4895 4350 and even RE19 have been better for anything above the 95gr Hornady. I have had good luck with Benchmark in other calibers and like I said the small bullets for the 260.
Varget was slower and did print good groups. I started with it.
The 140gr Partitions have taken more hogs than I can keep up with, and have been good on deer as well. Some folks like the 120s which have been accurate, but BTs have not performed as well for me.

I load the .260 for both rifle and pistol. I usually wind up going back to 4350. I've found BM to vary a little much for me, lot to lot. I do use it in my 6.8 with no problem.

Check your freebore, or lack thereof. My 25/06 Encore has almost none. SAAMI MAX OAL-3.250, but anything close to that shows excessive pressure. I am limited to 3.238 with 115 gr. BT.
This condition is also not uncommon with some Savage guns.

Bob
I have 3 books here by my computer for reference Speer # 13 Nosler #6 and Modern Reloading 2nd edition and none list a load for any 6.5 cal with B.m. that I can find. All show 4895,4350,varget,4831 re 19 .The modern reloading 2nd edition lists 23 different powders for the 120 gr bullet alone in the .260 ,none are B.M. I'm sure its a good powder for some applications just dosn't seem to fit the 6.5 group.I use H 4831 sc or IMR 4350 for my Sweeds and 6.5 Rem Mag.

karl: I will probably abandon my Benchmark testing in the 260. From the Quick Load information provided on the 24 Hour Campfire Post with 120 BT bullets it looks like one would need to back off between 4 and 5 grains to be into safe territory. I am sure that this would leave way more air space in the case than I would like.

Cherokee Tracker: I should not have started .5 under max. Most of the time, especially with load date that I cannot confirm from multiple sources I will start 2 - 3 grains under max and work up in .5 increments. This being Hodgdon Data, and the fastest load listed I wanted to check it out. This being a faster powder than normal for the 260 rifle, I thought I might get a little more out of it in the handgun.

Sawfish: Normally when I order a new barrel I will send in a Dummy Round to have the Throat Optimized for long seated bullets in my single shot handguns where length is a non issue.
This is a Bullberry barrel I got from Mark Hampton. It is probably throated to factory specifications. I would not think my 107 SMK loads would have a free bore issue.

Junebug: You are correct about the lack of data using Benchmark in this application. No way to double check from multiple sources. I would have assumed that Hodgdon would have better data on this powder unless it has changed over the years.

I pulled the remaining 14 rounds and reloaded them with H4895. I will probably get the Encore sighted in Thursday.

Bob R