F Class cartridges

RDavies · #1 Postby **RDavies** » Sun Oct 16, 2011 7:49 pm

These are my main F class cartridges.
L-R. 284/168 Berger,
6.5 Gertrude/140 Berger,
6 Dasher/103 Copper head
22 BR

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The 6.5 Gertrude is just a 25 WSSM necked up to 6.5mm and neck turned so the neck thickness is the same as standard turned cartridges, unlike the 0.022" they come with. It is also throated out to suit 140gn pills. It is like a scaled up 6BR, with good neck length and the same 30 degree shoulder as the PPC/BR.
It will shoot 140gn bullets at the same speed a 6BR shoots 105gn bullets, or 130gn bullets at 6 dasher speeds.

DaveMc · #2 Postby **DaveMc** » Mon Oct 17, 2011 7:00 am

Gertrude certainly looks like a grown up 22BR. Will be really interesting to see how she goes.

bruce moulds · #3 Postby **bruce moulds** » Mon Oct 17, 2011 11:52 am

rod,
what is the length of freebore on your 284 reamer?
bruce.

RDavies · #4 Postby **RDavies** » Mon Oct 17, 2011 12:08 pm

Cant remember the freebore, but I did run a throating reamer in to clean the throat up a bit after 1000 rounds or so, normaly its sits about 2-3mm further in the case..

bruce moulds · #5 Postby **bruce moulds** » Mon Oct 17, 2011 12:24 pm

how much of the bearing surface is in the neck rod?
bruce.

RDavies · #6 Postby **RDavies** » Mon Oct 17, 2011 12:42 pm

About 2-3mm with the 168 jammed 0.015", not much, but enough. The 168s are very similar to the 180s, cant tell the difference looking at them.

The standard Shehane reamer cuts the chamber perfect for 168s, but you would want to throat it a bit for 180s, a few people have borrowed my throater for this.

bruce moulds · #7 Postby **bruce moulds** » Mon Oct 17, 2011 3:47 pm

thanks rod.
bruce.

DaveMc · #8 Postby **DaveMc** » Tue Oct 18, 2011 7:14 am

Here is my latest shehane reamer. It was built for the 180 VLD's and supposedly OK for the 168's (I personally haven't tried yet). Has about 6mm in Neck with 180 VLD's when jammed 10-15 thou. Have yet to try the new Hybrids.

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#9 Postby **AlanF** » Tue Oct 18, 2011 9:59 am

DaveMc wrote:Here is my latest shehane reamer. It was built for the 180 VLD's and supposedly OK for the 168's (I personally haven't tried yet). Has about 6mm in Neck with 180 VLD's when jammed 10-15 thou. Have yet to try the new Hybrids.

My reamer is identical with yours Dave except the the LEAD and THROAT dimensions are 0.021 longer (FACE to LEAD 2.420, FACE to THROAT 2.618). This is good for both the 180 and 168 VLDs but I am very keen to see if it suits the 180 hybrids (don't have any yet). Have you looked into this Rod?

Alan

RDavies · #10 Postby **RDavies** » Tue Oct 18, 2011 4:29 pm

The standard lead which the Shehane had would be perfect for the Hybrids as they sit further out to touch the rifling. I dont have any measurements.

DaveMc · #11 Postby **DaveMc** » Tue Oct 18, 2011 4:56 pm

just measured a hybrid up and touching lands has about 5mm bearing surface in case for OAL of 3.278 inch. I suppose Alan yours will be 0.5mm less roundabouts (unless my throat has eroded a little).
Cheers,
Dave

ps Rod How about divulging your barrel manufacturers too??? any chance?

mine was standard savage target action and bedded Savage F class stock with cracker of a Truflite barrel. the new 1 in 9 twist 6 groove SG. ordered through Phil Mastin.

#12 Postby **AlanF** » Tue Oct 18, 2011 5:17 pm

Thanks fellas. Glad to hear they need a slightly shorter throat than the VLDs Dave. I like to keep the boat-tail to bearing surface junction clear of the case neck shoulder junction - the 180 VLDs are very close, so it sounds like the hybrids will be nicely clear (assuming jammed).

agro · #13 Postby **agro** » Tue Oct 18, 2011 5:45 pm

The Gertrude looks like a 6br on steroids!!!!!

RDavies · #14 Postby **RDavies** » Wed Oct 19, 2011 5:22 am

Agro, 6BR on steroids is exactly how I desribe it.

As for Barrel manufacturers, the 6.5 Gertrude is also on a new True-flite SG rifled 6 groove, 8.5 twist from Phil Mastin. I,m confident (hoping)it will also return to being a cracker once I retune it.
I also have a Broughton 6.5 barrel coming to be chambered for the gertrude as well.
The new 284 is a Broughton 9" twist.
The old 284 is a Maddco 10" twist
The 6 Dasher is a Maddco 8" twist from Pro-Cal(with another Broughton being chambered now).
22BR is a Lilja 9" twist with 1000s of rounds through it, but has been CSC treated. (Catalytic surface conversion, google it).

Any future barrels will be either True-flites, Broughtons, or Liljas