6.5 Grendel Compressed?

[goodlookin1]

TestPilot, thank you very much for the data. I will definitely take a closer look at those suggested loadings. It seems right off the cuff that they are very conservative, which is what Rust seems to also indicate. That said, there is a lot that can be extracted from that data, so I thank you.

Rust, thanks for the info on the resizing. I dont know if i'm going to try doing that. It makes me very nervous trying different "unlisted/unproven" loads for fire-forming. Although, the temptation is still there due to the decreased cost of the brass. Have you found that fire forming 7.62x39 brass doesnt last as long as the Grendel brass? Or maybe a better question is: How many reloads can you get from fire-formed 7.62x39 brass?



On a side note: I went to the range yesterday and shot all my loads. I started at Rust's suggested load of 27 gr and made 10 round groups, incrementing the groups by 0.5 gr each, all the way up to 29.5 gr, which is the listed max. All were loaded to 2.26". I found that all reliably cycled the gun and none of the groups showed any signs of excess pressure. It seemed that the 27 gr - 28 gr loads had noticeable drop and quite a bit less speed, just from seeing the time between the shot fired and the dirt splash. I did have an issue with the gun getting jammed up though. There were two ways it was getting jammed up too: One was a bad feed and would lock up in the feed ramps.....the other would feed but not fire or extract, and then it would not unlock and let me pull out the round (I'd have to take the upper off completely to get it out). I think it was either:

1) The magazine. It looks like the lips are getting a little wavy and worn. I have some new C-Products mags on the way, so hopefully those will feed fine.
2) The cartridge OAL. Possibly a bit too long? All were exactly 2.26".
3) The feed ramps. Barrel has deep M4 feedramps cut into it, but not into the upper receiver. I am thinking about dremeling them out and polishing them up.
4) Not enough oil on the bolt. It seemed to dry up really fast and was not allowing the bolt to unlock and twist out of the teeth to eject the round.
5) I was not crimping and the brass could have been catching on the feed ramps.

Any ideas?

Thanks for all the input so far.

[Rust]

I have not loaded any of my fireformed brass (or any of my brass for that matter) enough times to wear it out. I've done a lot more shooting with the initial fireforming loads themselves than with full charged formed cases. I'm up to a couple hundred cases now, and will probably start working on finding good loads for them rather than forming many more. Another method you can try is to hydroform the cases if you don't feel safe shooting unpublished loads. There are threads and video on www.65grendel.com posted by "Chopper" that explain the process if you're not familiar with it. There are also several threads there on necking down and fireforming 7.62x39 if have not seen them yet.

[gemihur]

I don't 'run' with the Grendel. I 'walk'. I shoot the T/C contender. It's tough to find load data that describe the pressure signs of various loads. Your AR's can handle a tad more than my break-action. Just got a 17" Coyote Arms bbl. and necked and trimmed some spent AK brass. After exhaustive research and much anguish I compiled a trial batch of Sierra 140 gr. soft point boat tail ahead of 19 gr. IMR 4198 using small rifle magnum primers. Would you believe my maiden load shot 1.1" group of three @ 100 yds!!! How's that for luck?
I will admit that the barrel didn't like as much, the more common large primer pockets that I had filled with standard large rifle primers, whose group opened up to close to 7". I think I'll reserve those brass to work up lighter bullet loads and utilizing large rifle magnum primers at a later date.

[billmaykafer]

how does the grendal 6.5 compare to Swedish light infantry rifle 6.5X55 ?

[ar15barrels]

how does the grendal 6.5 compare to Swedish light infantry rifle 6.5X55 ?

It wishes it could become one.

[gemihur]

The 6.5 Grendel is Bill Alexander's contribution to the AR line of options. It's based on the 6 PPC case which is derived from the 220 Russian. Brass can also be formed using 7.62x39 cases. Try to use a 6.6x55 in your AR-15 and it will wish it was a Grendel. Check this baby out! Alexander Arms sets it's trajectory tables to zero at 600 yds! Bill claims that it is an 800 yd. cartridge. (Lofty)
The standard weights are 90, 110, and 123 gr. bullets. Due to my existing inventory I've used the heaviest of suggested projectiles, 140gr., Alexander claims that the 130, and 140 gr. do best downrange. I'm anxious to develope loads for the lighter side of bullets.

[gemihur]

I can't feed my contender 6.5x55 anyway. Bad medicine!
Leave it to the mausers.

[acourvil]

Alexander Arms sets it's trajectory tables to zero at 600 yds! Bill claims that it is an 800 yd. cartridge. (Lofty)

I was having no trouble hitting steel at 860yards with my (fairly new) Grendel last weekend. The 107g SMKs seemed to spread out a bit at that range, but the 123g and 129g had no problems.