Remington CDL .30-06 twist rate

[Shuz]

I have a Remington .30-06, which I believe is perhaps an older CDL model, based on it's looks and features. Here's the issue. The rifle shoots the RCBS 30-150FN weighing 160g checked and lubed very well, achieving a tad over 1" at 100 yards, with 21g of IMR 4759. Velocity is in the 1850fps arena. I tried my NOE 311-165FN, weighing 172g checked and lubed with the same powder and different loadings and get 4 to 5" patterns,not groups at 100 yards, altho this boolit gives less than 1" groups at 50 yards. I suspect that my rifle has a 1:12" twist, so I measured it. As best as I can determine with a patch that may have slipped a bit, my rod did not achieve 2 turns within it's 22" run thru the bbl. Therefore I concluded it must be a 1:12. I have a query into Remington to ask if the twist on my rifle could be 1:12, as their current literature calls for 1:10 in that caliber.

Have any of you experienced similar issues with a Remington 700 in .30-06?

[Char-Gar]

Anything can happen, but if your Remington 30-06 has a 1-12 twist it is a fluke. Remington made their 308 Winchesters with a 1-12 twist, but their 30-06 twist has always been 1-10.

It is much more likely that you goofed up the measurement of your rifle barrel. The old tried and true method is as follows.

1. With a rod that revolves on the handle, insert the rod with a tight patch from the muzzle and push it down about 2/3rd of the way down the barrel.
2. Put a mark on the rod at the muzzle.
3. Attach and old fashion clip on clothes pin to the rod with it pointing straight up at the 12 O'Clock position. Place it just behind the mark.
4. Draw the rod out stopping when the pin is again straight up at the 12 O'Clock position. Once again mark the rod at the muzzle.
5. Measure the distance between the two marks and you will have twist, if you have done everything correctly.

The difference between how your 150 and 165 grain bullets group, will not be found in the twist, but some other cause. It is impossible to even give an educated guess without more and extensive data from you.

[Motor]

According to their web site the 3006 CDL is 1-10

I think 1-12 should still stabilize a 172gr bullet. The length of bullet makes a difference too but I can't see length being a problem with a cast bullet. Now if it was some kind of j-word with a long sleek profile and boat tail that would be different.
Motor

[Blackwater]

I can almost guarantee you that your gun is 1:10" twist. I think you just need to remember that the chamber takes up @ 2.5" of your 22" barrel, leaving only a little less than 20" of actual rifled section to measure your twist with. The difference between 1:10 and 1:12 really isn't that great, and CAN be difficult to measure. I think if it were me, I'd take some stiff tape, like plain ol' masking tape, and make a wrap with a "tail" left to use as a pointer. I usually keep mine straight up, but you can use any point as a reference. That's your starting point. Use a VERY tight and lubed (I like grease better for this simply because it's a tad stiffer) patch so slippage is minimized, and make a mark at the rear of the receiver or whatever index point you wish, and then shove it in until the tape "tail" again returns to your chosen index point, and make another mark on your rod at that point, and measure the distance between the two marks. This is still less than quite accurate, but should give you a pretty close idea of what your twist is. This little trick can come in handy at times, but like any measuring job, has to be done very carefully and with great attention to the process and fit. FWIW?