A 260 Imp 30˚ case (right) next to a factory 260 Remington case (left). The 260 Imp 30˚ has a case capacity larger than a 260 Rem. but it incorporates a slightly longer neck and the renowned and accuracy proven 30 degree shoulder angle. The net result is that the 260 Imp 30˚ is a very efficient, consistent and accurate performer, with the capacity to push the 139-142 gr. bullets in the 2900+ fps range.
Note: If you are looking for someone to chamber your rifle or re-barrel an existing rifle in the 260 Imp 30˚ cartridge, Fred at Sabreco, Inc. in Skippack, PA (610) 584-8228 can help you with this. He has the reamers for the cartridge as well as the head space gages for the cartridge, and has had extensive experience setting up and chambering many barrels and rifles in the cartridge.
The 260 Imp 30˚ Cartridge
The 260 Imp 30˚ has some excellent attributes:
- Very easy to make! Chamber uses common and readily available 308 Win. head space gages (i.e. no special head space gages required).Die Sets Readily Available - Call (215) 348-8789 To Order
Loading die prices:
260 Imp 30˚ Modified Case - $15.00
Working With The 260 Imp 30˚
At this point, I have two barrels chambered up in the 260 Imp 30˚, and both of them shoot very well. The cartridge does not seem to be finicky and it seems easy to load for. In addition, there are a lot of popular powders that work very well with the cartridge, including H4350, IMR 4350, Reloader 17, VihtaVuori N150, N550, and N160, and H4831SC. I have worked a fair amount with H4350 and Reloader 17, and both have no problem getting the 139-142 gr. 6.5mm match bullets runing well up in the 2900+ fps range.
Some Initial Chrono Results:
With 30" barrel with chamber throated long for the 142 Sierras:
42 gr. H4350 with Sierra 142 = 2685 fps
43 gr. H4350 with Sierra 142 = 2760 fps
44 gr. H4350 with Sierra 142 = 2833 fps
45 gr. H4350 with Sierra 142 = 2903 fps
With 26" Barrel with the shorter throated reamer below. Brass used was fireformed
Lapua 260 Rem brass, primers used were CCI BR-2 primers. Bullets were
loaded at 2.870" OAL and magazine fed from an Accuracy International
magazine (AICS short action magazine). The 140 gr Hybrid bullet hits the
lands at around 2.905" OAL in this chamber, a Sierra 142 hits the lands at
around 2.845" OAL in this chamber and a Berger 140 gr VLD hits the lands
around 2.873" OAL in this chamber.
42 gr. H4350, Berger 140 gr. Hybrid bullet = 2686 fps
43 gr. H4350, Berger 140 gr. Hybrid bullet = 2759 fps
44 gr. H4350, Berger 140 gr. Hybrid bullet = 2820 fps
45 gr. H4350, Berger 140 gr. Hybrid bullet = 2888 fps - Light Compression
46 gr. H4350, Berger 140 gr. Hybrid bullet = 2915 fps - Compressed Load
42 gr. RL17, Berger 140 gr. Hybrid bullet = 2769 fps
43 gr. RL17, Berger 140 gr. Hybrid bullet = 2841 fps
44 gr. RL17, Berger 140 gr. Hybrid bullet = 2919 fps
45 gr. RL17, Berger 140 gr. Hybrid bullet = 2997 fps
39 gr. N150, Berger 140 gr. Hybrid bullet = 2794 fps
40 gr. N150, Berger 140 gr. Hybrid bullet = 2832 fps
41 gr. N150, Berger 140 gr. Hybrid bullet = 2889 fps - Some pressure
42 gr. N150, Berger 140 gr. Hybrid bullet = 2955 fps - Too much pressure
Reamer Prints Below (two different prints)
The 260 Imp 30˚ reamer just below is throated and was set up for magazine fed rounds out of a short action while keeping bullets close to the rifling at a magazine length OAL
Short Throat Reamer Above
Long Range Reamer Below
The 260 Imp 30˚LR reamer below is throated long and is ideal for loads keeping the full bearing surface of 139-142 gr. bullets forward of the neck/shoulder junction of the case.
Max Case and Trim Length for 260 Imp 30˚ Brass Cases
There is no formal established max case or trim lengths for the 260 Imp 30˚ brass. The author suggests the following for guidelines:
Max Case Length: 2.035"
Trim Length: 2.025"
Copyright 2005 Robert Whitley. All rights reserved.