Kirby Custom 300 RUM shooting 6" + groups @ 100 yards

Discussion in 'Equipment Discussions' started by ricka0, Oct 26, 2005.

  1. ricka0

    ricka0 Well-Known Member

    Nov 8, 2004
    Kirby Custom 300 RUM shooting 6\" + groups @ 100 yards

    I went to the range Sunday with my 375 & 300 Kirby built RUMS, each sporting Lilja 30" SS #7 contour tubes, Holland QD brakes, trigger jobs, #8-40 mounts, custom stocks, excellent Burris Xtreme rings and 25 MOA bases. I also took my factory 270 WSM a-bolt.
    I've shot the 375 RUM in the past. It sports a Loopy 4.5-14x50mm LR VX-III. I shoot 260 Accubonds and it's a tack driver. My 270 WSM A-Bolt usually shoots about 1/2MOA with good reloads. This was my first outing with the 300 RUM with the slow twist 1:12 barrel. This gun was designed specifically for my friends ranch outside Great Falls, MT (where the big bucks usually stand 400-500 yards out but you can't see anything past 700 yards - thus a lighter/faster bullet and a slower twist).

    I loaded the 300 RUM/Allen/Lilja/Savage with 155gr SCENAR and IMR-4350 starting at 83gr and going up to 88.5 - The brass was new Federal outside neck turned with my excellent K&M turner. Whatever primer they come with. Prepped the primer pockets.

    The 270WSM was loaded with once fired Win Brass (re-sized, neck turned, primer pockets uniformed), 135 gr MK and 54 - 59g of IMR-4350 (yes, it is the best med burning powder).

    The first group shot well, slightly under 1 MOA. I then shot the BIG 375 RUM, then the 270 WSM. I then went up a 1 gr in powder on the 270 and the 300 RUM. The 270 groups got tighter. To my surprise the group got bigger on the 300 RUM. I continued to go up grains and the 270's groups shrunk while the 300 RUMS kept getting bigger. I made sure the barrels didn't get hot and cleaned them regularly. Soon the 270 WSM was shooting nearly 1/2 MOA groups with no signs of pressure. The 300 RUM was now shooting 6-7" groups with no signs of pressure. I was ready to cry, I had planned on using the 300 RUM for a year on my friends ranch. The 270 hurt my shoulder and dinged my head. The 5 lb factory trigger was very difficult to control after getting used to Kirby's triggers.
    It started to rain. Maybe the bad groups were from the rain. What is the impact of rain on groups? But the 270 and 375 continued to shoot great.
    I went home very disappointed. But on the drive home, I remembered what my auto mechanic told me the last 5 times I called him to report a problem. [ QUOTE ]
    <font color="purple"> What's the last thing you fixed? </font>

    [/ QUOTE ] I had just mounted my NightForce 3.5-15x56 with NP-R2 the night before. I was using the same Burris Xtreme rings I used on my 50 BMG when I wrote the article on the Burris rings (appeared this month in VHP
    I inspected the optics system and the 2 of the 4 screws on the rail had come 90% out and the other two were 25% out. The scope was flopping all over. A quick email to Kirby and he told me to [ QUOTE ]
    <font color="purple"> degrease the screws and screw holes before torquing the screws </font>

    [/ QUOTE ] I did that Monday nite, then loaded up 20 sighters using my cheap Rem once fired brass. I didn't bother to outside neck turn, sort on run-out, prep the primer pockets or anything else. I just needed to get it sighted in and try to get a 1" group. I had no idea what powder load the gun liked, so I just went with a conservative 86 gr.

    The first two shots showed it was 1" high an 1" to the left. 8 clicks latter I got this bug-hole group.
    BugHoles from quick reloads Check out the beautiful gun. Amazing results from brass that hasn't been fire-formed or prepped - 25 thousands off the lands. Nothing has been optimized and it still shoots bug holes.
  2. arthurj

    arthurj Well-Known Member

    Jan 29, 2005
    Re: Kirby Custom 300 RUM shooting 6\" + groups @ 100 yards

    I knew that thing would pull through! I am loving my ultra Kirby built for me.

  3. Mysticplayer

    Mysticplayer Writers Guild

    Jul 27, 2001
    Re: Kirby Custom 300 RUM shooting 6\" + groups @ 100 yards

    The best part with shooting well built rifles is knowing that if something isn't shooting right, there is a mechanical or load problem.

    You found what is all too common these days. Scope rings loosening up. Not because they are poorly designed or mounted wrong but because of that wonderful preservative oil that is poured on everything.

    This stuff works awesome at what it was designed to do. Make sure nothing seizes together. Pretty much makes proper tightening impossible. Been caught that way several times recently.

    Best thing now is to take some aerosol brake cleaner and clean everything especially the bolt holes. Now when you reassemble, things will hold. In fact, the biggest problem now is that they don't want to come apart...

  4. Buffalobob

    Buffalobob Writers Guild

    Jun 12, 2001
    Re: Kirby Custom 300 RUM shooting 6\" + groups @ 100 yards

    Big bore

    You must use the same auto mechnic as me! I think I pay mine extra for his witty sayings.
  5. reed mosser

    reed mosser Well-Known Member

    Sep 16, 2003
    Re: Kirby Custom 300 RUM shooting 6\" + groups @ 100 yards

    I have had problems with my 30-338 laupa imp loosening up scope bases too. Mine is a savage with Ken Farrel bases. I have a brake on the gun but is is heck on the scope bases. At least you found out what the problem was. Have a good hunting season