Home Forums Reloading Big Game Rifles Need assistance - strange results today with 6.5x55 and Hybrid 100V

I had some strange results with extremely high velocities relative to load weight, and I could use some ideas as to how to proceed.

Steve Gash's article "A Metric Marvel: 6.5x55 Swedish Mauser" in Shooting Times, October 2015 had always had me interested in trying Hybrid 100V in a modern action 6.5x55. I had grabbed some Hybrid 100V a while back, and decided to give it a try. The rifle is a Savage 110 long action (started life as a .30-06) rebarreled to 6.5x55 with an ER Shaw barrel, topped with a Leupold VX-R 3-9 scope.

The loads were developed using a 140 gr Hornady Interlock, Federal LRP and new (never fired) R-P brass (ran the necks over the expander and trimmed/chamfered/deburred). COAL used was 3.0".

Both Mr. Gash and Hodgon state 44.5 gr of Hybrid 100V is the max load with this bullet, and with this charge I was expecting to achieve around 2650 fps.

I started at 42.0 grains of powder, about 5% below where I planned to end up as max. I was extremely surprised when the 42.0 grain load, 3.5 grains below max, showed an average velocity for 3 shots of 2654 fps. I was already at what I expected to be peak velocity.

I assumed the issue was my LabRadar. I checked the alignment, settings, distance, orientation, etc. I couldn't find an obvious error. I was very careful to check the alignment and distance, and I decided to try the next charge, 43.0 gr. I was hoping to see the velocity drop considerably to prove something was wrong with the LabRadar, but 3 shots at 43.0 gr have an average velocity of 2713 fps.

At this point I was still thinking the LabRadar had something wrong that was producing a repeatable offset, where the recorded velocities would be consistent but erroneosly biased to a higher reading.

To check, I stopped shooting the Hybrid 100V charge ladder and switched to a box of Federal fusion 156 gr, that in other rifles with similar barrel lengths had shown a velocity of 2450 fps. I expected the velocity measurements would come in much higher, if the LabRadar was the culprit. I fired 3 shots and the average velocity was 2444 fps, so dead on.

Then I tried a different handload I had worked up in the past, and it had shown an average of 2425 fps in the past. 3 shots on this day showed 2400 fps average.

I believe the LabRadar was giving me accurate velocity data within it's tolerance. I never get exactly the same velocity from trip to trip, but usually with ing +/- 10 to 20 fps, and with only 3 shot groups I felt the control cartridges were reading correctly (when I record my baseline velocity data for a load, it's usually 6 to 10 shots, so I expect more variance with a small sample of 3).

I just checked the zero on my RCBS 505 scale I used to weigh out the charges yesterday, and it was dead on. I also verified with my Lyman Check Weights to verify measurements in the 40ish grain range would indeed be accurate, and they were.

At this point I believe the charge weights I loaded were accurate, and the loads are very hot relative to the charge weight. I have more loads up the charge ladder to 44.5 gr I have not shot, so when I pull them down I'll check the charges.

I'm not sure what's going on with this load. Any ideas? Anyone worked with this powder in the 6.5x55 before?

Different lot of powder, different rifle, custom barrel, it's not that unusual for a charge that's 3.5gr didfferent to give you your expected velocity. That's why we start lower and work our way up.

100%.

Different brass thickness is usually the biggest difference for me.

But, how did the 42.0 gr load shoot? The 43.0 gr load?

As far as the unexpected velocity goes, that's why its great to have access to a chronograph when working up loads.

Having said that, I recently had a somewhat similar experience using H4350 behind 168 gr Barnes TSX in a .300 WSM. Barnes lists 69.4 gr as their maximum charge with this bullet, giving them 3126 fps. I hit 3102 fps at 67.0 gr and 3152 fps at 68.0 gr. Unlike you, though, I, perhaps stupidly, went ahead and fired a 69.0 gr charge that I had loaded, which gave me 3181 fps. And, sure enough, the bolt lift was a little bit sticky on extraction.

OTOH, had I not been using a chronograph during this session, I'm certain I'd have fired that 69.0 gr load anyway, and reached the same conclusion.

All the above should be considered, and also another possible factor: ambient temperature.

Good post RR. H100V has a reputation as being temperature sensitive. Was it hot out, cartridges sitting in a hot vehicle in the sun etc? MD discussed this in one of the GG's.

Good luck and shoot straight y'all

While not a 6.5x55 I ran into a similar situation this weekend. I wanted to work up a new 25-06 load with N560 using 133g Berger EH. I input all of my data into quickload and determined a max capacity of 56.7g. I started 10% below that target with an OCW array. Even my 10% below max charge loads were far, far faster than QL anticipated. at 51.5g I was at 2950fps (2760 expected). At my second level of OCW charges (55.1g), the rifle hit 3150 fps. I still had 5 levels of OCW to go through. I called it quits over worries of pressure issues. I had what I considered flat primers. Everyone on another platform disagreed and said they thought my primers still had some round to them after I posted pictures. I never experienced hard bolt lift, stuck cases, etc.

I had absolutely excellent results with 120g bullets using Hybrid 100 out of my 25-06 and never experienced temp sensitivity from it, but I did most of my shooting in the fall.

Quick follow up on ambient temperature - it was in the mid 80's that day. My ammunition and rifle moved from an air conditioned house, to my air conditioned car and, upon arrival at the range, the range bag and rifle were moved from the car to the shaded firing line bench. I would say the ammunition moved from being at around 70F to 85F when it was fired. Ammunition did not sit out in the sun or inside a hot car.

I did wait between strings of fire to insure the barrel had cooled. I don't really have the experience to say definitively if 85F would or would not cause the velocities I observed vs. the velocities I expected, but I'm leaning towards no.

I have loaded 5 round samples of 42.0 gr, 42.5 gr and 43.0 gr (previously I shot 3 round samples at 42.0 and 43.0, mostly for velocity check and not really trying for best accuracy) and I will re-shoot for accuracy and with my LabRadar for velocity. If I can find the accuracy I want at one of these charges with 2650 to 2700 fps, I'll just go with that load.

I think you are putting too much thought into it...

a barrel and action will tell you what IT likes in particular, whether velocity is high or low.

Too many variables to include spec on your barrel which may be totally different on the next one made after it, or the one made before it.

How the brass is after being fired is what I'd pay attention to also...lose primer pockets, etc.

If the case is still tight, then things should be fine...

all these reference manuals and reload manuals are guides, NOT Bibles. Each action and barrel is an entity unto itself.

I've had barrels and actions that have no problem going past what is listed in a manual, and then some...
yet the same barrel and action will pop primers on another STARTING load, right off the same page...

Let your rifle tell you what it likes, not some load reference that tells you what it likes...

yet next batch of the same powder can give totally different results.. hence why I say they are guides... NOT Bibles.

Good post. It’s definitely different times we live in. Back in the day, most of us were self taught and we used those manuals as reference. Not swaying too much off the beaten path. We kept a very close eye on pressure signs. Yeah I know, guys now say the brass is no indicator of pressure. We were way more in tuned to what the rifle was telling us. The report (or crack of the load), the smoke, even the smell. These newbies have never had to develop loads for 5 or 6 rifles chambered for the same cartridge, on the same day. That’s where it gets into a complex math problem on law of averages. Yet, they struggle with developing a load for ONE fn rifle. These are the days. It can’t be stressed enough to start low and work up. We (in the know) say this often, but it lands on deaf ears of the newbie. As they want to be told what load to use, what load is going to produce the smallest group and be safe in their rifle. They see it in a magazine article or the internet, so it must be true. Right?

This is what I think of every time someone wants to know whether or not H4831 and H4831SC load data are interchangeable. Yes, no, maybe...listen to the rifle (and the chronograph!!!).

It’s called instant gratification bud. Seen it and yes it does get tiresome.

Well Hodgdon makes no distinction between the 2. But it relates to my other post.

Smell of the smoke? Complex math problem on law of averages? I've been reloading for about 45 years, but I must need to up my game! LOL

As opposed to the temperature in your air-conditioned house or your shut-up car sitting in the sun.

^^^^^^^Tell me you’re a tool, without telling me you’re a tool.^^^^^^

I shot the initial loads again to check accuracy, and 42.5 grains of Hybtid 100-V is it.

This was a good learning experience.

Thanks for all the responses.

Ummm... okay...

" You're a tool"..... Feel better now? If so, glad to help out...

you're welcome...

Hint.




Fhuqking LAUGHING!....................