resizing 6.5 grendel to .243 LBC

[The Wolverine]

I honestly do not know what the differences are, I have never looked at a Grendel chamber specs, or the 6mmAR chamber spec for that matter. I knew what I wanted, and built it.

The 243LBC chamber specs are on the BHW forum if you have Grendel specs, you can compare them. http://www.blackholeweaponry.proboar...play&thread=56

Call BHW about the 243LBC, I did not realize it was not on there site.

[cjgemm]

Wow, My 22" 6XC bolt gun can only push a 105 to 2970 fps using 10 more grains of powder. Maybe David Tubb should come talk to you.

[The Wolverine]

Wow, My 22" 6XC bolt gun can only push a 105 to 2970 fps using 10 more grains of powder. Maybe David Tubb should come talk to you.

I have not chrono'd the 105gr, but your 6XC should beat my 20" 243LBC by 240fps or so.

Paul

[cjgemm]

I stopped at ejector flow. according to QL that was about 58-59000 PSI. I could make them go faster 3000+ , but backed off .5 gns to save brass barrel. According to your load QL puts you about 59000psi and 2719 fps. Granted that was using the 6mm AR. To get 2800+ I had to add a grain(29 gns 8208) and the resulting chamber pressure increased to 66000psi.

[The Wolverine]

The 2800+ I am getting is with a 100gr partition, which is a lot shorter than a 105gr, I am expecting to get low 2700 with the 105's

[cjgemm]

Above was calculated with the Nosler 100gn part. loaded at 2.195. I have found QL to be sometimes inaccurate(didnt do a very good job with my 284win) , but still find it a useful tool. Just thought I'd pass the info on. From what Ive read mid 2700 should be a realistic number for a 105 out of a 26" barrel.

[The Wolverine]

Well, a three shot string with 28.5gr of 8208 the 100gr Partition is running 2803, 2789, and 2813fps, with no pressure signs at all, primer not even starting to flatten, so your speed to powder numbers are not too far off, but I do not think I am running anywhere near the pressures you are showing.

BTW, I believe my next build will be a 20'' Grendel, so I am not trying to say the 243LBC is a replacement for the Grendel, more like a compliment to it.

Paul

[JASmith]

Hodgdon shows just under 2750 with 100 gr Ballistic Tip with pressures at almost 50000 psi. You are not likely to see pressure signs until you get closer to 57000 psi.

Going above 50ksi is likely reduced bolt life...and the reason Bill Alexander specified a SAAMI pressure limit that keeps working pressure under that.

[Drifter]

Forgive my ignorance, but would it be possible to form 243 LBC brass using a 6.5 Grendel full-length S-type bushing die, and changing the expander to 6mm and using a smaller appropriately sized neck bushing?

First time through might be tight, but after fire-forming, it should be easier.

Possibility, or not even close...?

[bwaites]

Forgive my ignorance, but would it be possible to form 243 LBC brass using a 6.5 Grendel full-length S-type bushing die, and changing the expander to 6mm and using a smaller appropriately sized neck bushing?

First time through might be tight, but after fire-forming, it should be easier.

Possibility, or not even close...?

It should be possible using bushing dies, though I'd probably step it at least once, and maybe twice instead of trying to do it in one leap.