Question on 6.5 Creemoor load

[coffeediver]

Doing a Satterlee ladder load test for my new 6.5 CM. I had some IMR 4831 that is at least 10 years old if not older. The Hodgdon website list starting minimum load 38.9gr @ 2394fps and max load 44.3C @ 2705fps. I used new unfired and sized Starline brass, CCI BR2 primers and Hornady 147gr ELD-M bullets.

The rifle is a new Savage 110 Precision 24" barrel with muzzle brake and only 80 to 90 rounds through it before this test. It was a 10 shot string that started at 42.5gr going up .2gr per load to 44.3C My velocities started at 2751 and ended at 2870 measured with the Magnetospeed V3. I did not show much in the way of pressure signs on the brass. I am shooting at 6200 ft in altitude.

Is that much muzzle velocity telling me that I am doing something wrong. I do load with a RCBS chargemaster and then verify with a second scale. I used other powders for testing also such as Winchester Staball 6.5, IMR 4350 and Varget. Those powders were pretty much where the Hodgdon website said they should be. The IMR 4350 is about the same age as the 4831.

Any thoughts,

Thanks

 

[dstoenner]

Maybe at 6200 feet your humidity is very low and your powder is very dry. So 42 grains has more chemical to create more velocity. Newer powder may not have dried out like your 10 year old powder

just a thought

 

[piie]

New brass - less volume, greater pressure? Check what subsequent shots do?
Also, what was the barrel length used by Hodgdon when they crested their load vs your 24”, and even if it is the same, barrels differ...

if you dont see pressure signs, then you are ok

and powder batches differ (not just in age - the batch they tested with could be way different than what you used. Also, was your COAL the same as what they tested with?

The data from the manufacturers are not a goal, it is a guide.

 

[6milphil]

Your starline brass has considerably less internal volume than the hornady brass the hodgdon data is based on.

 

[Rob01]

Yup probably the brass but did you measure your OAL to lands? Savages are known for some coming in with short chambers so you would be jamming into the lands at what would be factory ammo lengths.

 

[coffeediver]

I have not measured the lands on this rifle yet but loaded all rounds to magazine magazine COAL 2.8 inches.

 

[Rob01]

Some savages even at factory oal are jamming into the lands.

 

[coffeediver]

Some savages even at factory oal are jamming into the lands.

I will measure that as soon as I can but if that was the issue than I would think the other powders I was testing would have had the same issue.

Barry

 

[Rob01]

Possible but hard to say 100%. Who knows you might just have a fast barrel. That happens too. I had a 26” I was getting 2920fps with 140s.

 

[Hohn]

Your starline brass has considerably less internal volume than the hornady brass the hodgdon data is based on.

This. My top charge of 47.0 RL26 today was flashing 2900 from a 26” bbl with Starline LRP.

Brass looked ok, but 2900fps with a 140 from a creedmoor IS a pressure sign. I’m backing it down to 45.8 where a good node seems to be and speeds are 2800.

 

[Hohn]

Some savages even at factory oal are jamming into the lands.

My Savage gives 2.386” CBTO to hit lands with 140rdfs and only 0.002” longer with 147 ELDs.

 

[Rob01]

My Savage gives 2.386” CBTO to hit lands with 140rdfs and only 0.002” longer with 147 ELDs.

What is the OAL with that load? Mag length or near SAAMI?

 

[Hohn]

What is the OAL with that load? Mag length or near SAAMI?

I don’t measure OALs because I normally single feed, but 0.040” jump fed fine from accurate-mag 5rd. With binder plate (the shorter one).

 

[Rob01]

Don't have any loaded you could measure? Just curious. It's not something that happens to every Savage but more than a few have come through with very short freebore. Well short of SAAMI .199.

That your load to lands fits in a mag with binder plate lends me to believe it is short also. A 147 ELD in a SAAMI chamber would be about 2.890" and that wouldn't fit in a AICS mag with binder. They usually stop around 2.870".

 

[Hohn]

I seated a 140 RDF in my dummy since my die was still set. 2.883” oal to give 0.040 jump. Fed in my A/M mag. Chamber as delivered from Savage.

 

[Rob01]

Yeah at that length it's sounds like it's actually over SAAMI spec if it and the 147, which would be .002" over that as you mentioned, would be .040" off. Odd that fits in the mag as Accurate mag lists 2.875" as max OAL in their mags. I always used 2.870" as max as that has worked in all the AICS mags I have used over the years except for the PMAG versions.

 

[Hohn]

The ogives are quite a bit different between 147 ELD and 140 RDF. The 0.002" difference is only valid using the OAL tool and a Hornady .25 comparator. Actual OAL difference at the lands is very different from 140RDF to 147 ELD. I'm at 2.92" at the lands if I recall with the 147 and it will not mag feed.

 

[Rob01]

Yes I understand the ogives are different and was my assumption on your post about the .002". Yeah you are definitely longer than SAAMI if you are at lands at 2.920". SAAMI chamber would be about 2.890".