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.204 freebore

Posted: Wed Feb 28, 2007 8:12 pm
by Hutch20
First off, hello, my name is Hutch20 and I'm a .204aholic ;)

Second, what's up with the HUGE gap :shock: between my bullets and the rifling.

Has anyone tested to see if there is a measureable difference in accuracy between the factory GAP :eek: and the much more bareable custom offerings?

Thank you for your time and patience :twisted:


Hutch

Posted: Wed Feb 28, 2007 8:46 pm
by gwglave
Hutch20
First of all, welcome the 204um. Bunch of great folks lurking about the forum and with most, if not all, the answers to your questions.
You might want to do a search through past posts. The question you asked has been asked and answered a number of times.
But, here's the short version, most .204's shoot their best when they are way off the lands. I've seen OAL's as short as 2.24" and as long as 2.31"
but usually nothing longer than that. The magazine in your rifle (unless you have a single shot) will dictate the OAL.
As an example, in my Rem 700 VLS, loaded rounds must be less that 2.30" to cycle thru the magazine. The optimum OAL for me is 2.28 - 2.29".

Rgds, Gerry

Posted: Wed Feb 28, 2007 10:43 pm
by acloco
I second what gwglave advised. 2.8 to 2.9 on my Savage as well.

Posted: Thu Mar 01, 2007 12:04 am
by Lee C.
The savage fv I have shoot's best at 2.263 with a 35gr. berger bullet.

Posted: Thu Mar 01, 2007 5:58 am
by Glen
Welcome to the Forum Hutch!!
For the most part the 204 doesn't seem to mind the jump. Just make sure you keep at least .204" in the case neck. Plus what was said above too. :wink:

Posted: Thu Mar 01, 2007 7:01 am
by Rick in Oregon
Hutch20: The other guys have it right. The 204 is one of those calibers that seems to like jump to the lands. In my case, I mostly single load for bench varmint shooting, so I load mine out long, too long in fact to fit the magazine.

My bullets in my Sako Model 75 Varmint only have .120" of bullet in the case, meaning I can't rough handle them at all, put them in my pocket, etc. Even with this long loading length, I still have a whopping .100" jump to the lands, and the rifle shoots 100 yard groups in the .3's from the bench. Not many other calibers would shoot that well with that kind of jump. Even when loaded to fit my magazine, the Sako will print under 1/2".

Look at these 32gr Blitz Kings loaded for my Sako, compared to the factory ammo you probably have there at home to get an idea of what I'm referring to.

Image

If for any reason you decide to load long, be sure to check bullet concentricity on a quality tool, as if not loaded with inline seating dies, it's not a good idea to load long. The rounds above have TIR of .0015". Be careful, shoot well, and welcome to the forum.

Posted: Thu Mar 01, 2007 4:43 pm
by rayfromtx
I spoke with a tech guy from Hornady yesterday about this issue. He told me that this cartridge was designed to work best with a minimum freebore of .130 in order to work best. He warned that shortening it by adjusting the chamber length would likely lead to pressure issues with their factory ammo.

Posted: Thu Mar 01, 2007 5:22 pm
by contender hunter
I just checked my 39 gr sierra load to see how much was still in the case ,here are the numbers - COAL 2.425 is .027 off the lands and there is .110 left in the case . Do you guys see any problem with that ?? Glen you mentioned trying to keep .204 in the case , that is the general rule isn't it ?? ?? Rick and Skipper and the Glenns where are you at with the 39 gr. sierra??

I only measured down to the boattail , didn't measure the part of the bullet that doesn't contact the case. so there is actully more bullet in the case .

Posted: Thu Mar 01, 2007 5:30 pm
by Hawkeye Joe
I'm 2.450 OAL .004 off the lands in my VLP and LRPV with the 39's.Never loaded this long . 2.280 is the longest load tested last summer. I now load to 2.263 OAL with no need to change... YET :eek:

Posted: Thu Mar 01, 2007 5:55 pm
by contender hunter
Hawkeye , did you see an improvement in group size with seating close to the lands??

Posted: Thu Mar 01, 2007 5:57 pm
by glenn asher
2.293"OAL I hadn't paid much attention, I just loaded to magazine length in both rifles. I am decidedly un-scientific about it, though :D :D .

Posted: Thu Mar 01, 2007 6:34 pm
by skipper
I did an experiment with my XR-100 last year and loaded so that the bullets were touching the lands. I didn't see any measurable difference in group size. The only thing I did notice was that I only had about .063 bullet in the case neck. That's just not acceptable.

I also experimented with various seating depths and settled on 2.255 for all the bullets I shoot. This produced the smallest groups which seems to defy claims of improved accuracy by loading into the lands. Even with throat erosion I haven't changed the seating depth. The .204 seems to be more or less indifferent to seating depth in a factory rifle.

Try some experimentation of your own. Use your favorite load and seat 5 at the recommended depth. Then load another 5 at .005 longer and so on until you get to about half the bullet diameter left in the case. See what your rifle likes the best. If your loading to less than half of the bullet diameter left in the neck you're probably sacrificing neck tension or concentricity to some degree.

Posted: Thu Mar 01, 2007 6:51 pm
by Hutch20
Been lurkin around fer awahl. Been reloadin fer a few yers also. the bi g gap kinda freeked me out. Jest recently got tha barrul broke in. Ain't sure about the best groups jest yet. I figure it's good enough to hunt with fer now. Once we get more daylight I'll have more time to play with all tha details.

So there's really no appreciable difference in performance or accurracy with a factory chamber vs. a custom/match chamber.


Hutch

Posted: Thu Mar 01, 2007 7:15 pm
by Rick in Oregon
Hutch20: No, that's not correct. The posters are saying the 204 seems indifferent to distance from the lands. A custom chamber, cut with the "204 Match Reamer" has proven many times more accurate than a factory chamber.

Not many here want to have a factory barrel rechambered, but after the factory barrel is shot out, installing a new custom barrel, chambered with the match reamer is an entirely different story. That would generate much better accuracy, and has proven so to those that have already gone that route.

You can read about this in Todd Kindler's Small Caliber News, and his book, "The Terrific Twenties". In the book, Kindler has the Pacific Tool and Gauge drawings and full specifications for this reamer. The master toolmaker, Dave Kiff did all the work on the reamer.

Posted: Thu Mar 01, 2007 7:27 pm
by Hutch20
Thanks Rick I geuss I read to fast. cuase what I said jest didn'e make any sence to me. I've got my bullets seated just deep enough to reliably feeed from the magazine.


Hutch