Cooper M21 20 Tac Excessive Jump

[ab_bentley]

I had a 20VT that liked bullets seated .070" off the lands and the LOAL never moved even after 2500rds, seat the bullets to the base of the neck and see what happens.


Adam

[Don-T]

FWIW, the leade in my Cooper .20 TAC is the same as your friend's. My comparator shows 1.900" base to ogive with 32 Vmax. However with 26.1gr of Exterminator, it actually shoots in the 2's if I haven't had too much coffee.

[Ganderson]

The 20's really don't seem to mind a healthy jump....I have a Sako 85 in 204 that no bullet will touch the lands and still be in the case neck....I just load it to magazine length and shoot 1/4 to 3/8 inch groups with factory and handloads. My 20 VT seems to prefer a long jump, my 20Tac does too and even my 20BR....I guess what I am saying is, don't be too concerned with the long throat. The 20's also in my opinion shoot tighter when you run them at max load or close to it....I would try what one poster already stated and that is to seat the bullets to the base of the neck and push them faster....I bet you will be surprised. Xterminator, RL10X and 2520 powders will just about get any 20Tac to shoot also.

Gene

[Larry in VA]

I’m mildly surprised that many aren’t aware of the pinned thread in the “Small Caliber Load Data” about Coopers test loads, especially since so many here are Cooperholics. It was/is my understanding that these were the test loads Cooper used at the time they were posted. Have not talked to Cooper people since Rob left so I don’t know what they are doing now-days.
That was a lot of work getting that info from Rob and then trying to decipher his hand writing.
Here is the link in-case anyone is interested. http://www.saubier.com/forum/showthread.php?t=1190
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As with all reloading data work up slowly to listed data and treat this load data as Max. ... Be

[Gale Johnson]

Just curious how your friends tac 20 is coming along?

I just started shooting a new to me Cooper MTV in Tac 20 last week. I shot 50 rounds of 23.5 H4198 and 32 gr Vmax seated with 2.250 Coal. While sighting it in my final group was under .2 . I wanted to try some 39 Blitzking and Reloader 10x so I loaded 12 test loads from 23 to 25.5 grains of 10 X, they are also seated at 2.250. The best loaded seemed to be the 25.5 grains, slight cratering of the primer, but not flattened, easy bolt lift, might be about max for my gun. They all shot well but that last test measured .240 and should be close to 4000 fps. I loaded up 50 of those and went out to test on live varmint. I have shot my friend's Tac some and really like them but wow, those 39 reach out with not much drift. I was hitting them quite frequent over 350, that is a poke for me. I am always still amazed how a guy can take one of these Cooper's, throw some loads together and shoot little ragged hole's in the paper.

I will try and post a few pics.

It is kinda strange that you are having those problem's with your friends gun, hope you got it worked out.

[Travelor]

Here is a link to my experience in returning a Cooper in 204 Ruger for rebarrel. Although my problem was a incorrect chamber, the saga of getting it rebarreled by Cooper might be of interest.

http://www.204ruger.com/forum/viewtopic.php?f=2&t=11290

Here is hoping your friends Cooper experience is better than mine.

[tim simbari]

Hemi,
You're still fairly moderate on the loads. My Predator shoots quite well with either 25.6 of R10X or N 133 over 40 gr. Vmax with velocity I couln'nt match with benchmark.
If you hunt with it, a big difference.