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PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Tue Oct 25, 2011 3:41 pm
by mmw1015
What problem will I get from over exceeding col?
I noticed that even with 2.800 the bullet is not touching the lands.
What range should I be looking at on bullet seating depth?

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Tue Oct 25, 2011 4:50 pm
by Joe O
Did you mean 2.300? 204 throats are long,And I doubt you could go 2.800, and keep a bullet in the neck.I find 2.350-2.355 to work or me.

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Tue Oct 25, 2011 5:07 pm
by Hedge
It's going to vary with your chamber. For Joe it works out at 2.350 - 2.355. For me, using a 40gr Vmax it's 2.980 measured from base to ogive using a Hornady comparator (comparator body is part of the measurement). Measuring from base to bullet tip (not accurate) is about 2.375"

To answer your first question, 2 things I can think of; the bullet won't stay in the case or the loaded cartridge won't feed from the magazine.

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Tue Oct 25, 2011 10:19 pm
by mmw1015
I'm shooting a single shot break over so magizine is not a problem. Bullet falling out the end of cartridge might be!!! Ha
Would the longer bullet length cause pressure problems?

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Tue Oct 25, 2011 10:25 pm
by mmw1015
I see that both of you are seating above the col max of 2.260, is this without problems. If not a
problem, what is the max you can exceed by?

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Wed Oct 26, 2011 12:11 am
by Hedge
Hasn't been a problem for me. In fact, I haven't found a bullet, yet, that can touch the lands and still stay seated in the case.
Since the rifle you're loading for is a single shot, your max COL will be to or jammed into the lands. You'll have measure your freebore to find out what that will be.

One thing that could pose a problem is that when your bullet is seated shallow, there is more of a chance of excessive runout. This causes the bullet to hit the lands slightly off-axis of the bore and affecting accuracy.

And, yes, pressure will be an issue with the bullet touching the lands. Develop your load carefully, watching for pressure signs. However, touching the lands isn't always a guarantee of better groups. The .204 seems to like a long jump.
My best accuracy loads have run to a jump of .170" depending on powder and bullet.

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Wed Oct 26, 2011 2:32 am
by Joe O
Hedge wrote:It's going to vary with your chamber. For Joe it works out at 2.350 - 2.355. For me, using a 40gr Vmax it's 2.980 measured from base to ogive using a Hornady comparator (comparator body is part of the measurement). Measuring from base to bullet tip (not accurate) is about 2.375"

To answer your first question, 2 things I can think of; the bullet won't stay in the case or the loaded cartridge won't feed from the magazine.
Hedge
Just to clear up some confusion,your ogive length can't be longer than the COAL.Must be 2.280, instead of 2.980,right?

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Wed Oct 26, 2011 9:07 am
by Hedge
Joe -

Partially correct. My measurement really is 2.980" base to ogive.

Probably wasn't very clear ('twas 0-dark-hundred when I wrote it) ;)

The base to ogive measurement was taken with the Hornady OAL gauge mounted on my caliper so, the gauge length (1.0") is part of the measurement. Subtract that inch and you get the true length. But, for comparison between rounds, knowing actual length isn't necessary as long as you take the measurements the same way.

The base to tip measurement was approximated using a steel scale. Just measured it on the caliper w/o the gauge: 2.347"

Hope that cleared it up. :)

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Wed Oct 26, 2011 10:35 am
by Fred_C_Dobbs
The rule of thumb for limiting runout is that your shank seating depth should be no less than the diameter of the bullet.

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Thu Oct 27, 2011 10:27 am
by Wrangler John
And to all the above, may I add that the .204 Ruger is a mystical cartridge - nothing truly applies to it that is accepted as normal for other cartridges. My best accuracy happens with the bullet seated to 2.260", even the little stubby appearing 26g grain Varmint Grenade. The exception is the 50 grain Berger HPBT which is seated to 2.300".

My experience is that seating out does nothing to improve accuracy. Why? Don't know but when they developed the cartridge that long throat was purposefully included. Could it be that when most bullets clear the case neck they still haven't reached the rifling lead, so blowby acts to moderate pressure, while establishing what could be described as a pressure bearing? If a piston moving in a close fitting tube is surrounded by a high pressure gas flow, it will self-center as it passes through. To establish this condition, a high velocity gas flow in the direction of travel is needed. That doesn't happen when the bullet touches the lands at firing. When the bullet enters the lead, it is centered and pressure rises to keep it that way, all the more so if the chamber is cut concentric to the bore. Most of the original Weatherby rifles had a "freebore" of around .75" and they shot amazingly well.

Remember what they said about the .204 Ruger? The case was too long to be efficient and accurate like the short fat cases, it used standard sized flash holes, the necks weren't right, the bullets too light, yada - yada. I bought into that FUD until I tried one, now I'm convinced the .204 Ruger is the supreme cartridge for 95% of varmint hunting, and it's a factory offering to boot.

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Thu Oct 27, 2011 10:44 am
by RAMOS
WJ,

Very nicely put. Especially like the reference to a "pressure bearing". Chasing the lands on a factory 204R is physically impossible anyway. COAL should be accuracy driven, the proof should be on the paper.

Jon

Re: PROBLEMS WITH EXCEEDING COL of 2.260

Posted: Sat Nov 05, 2011 5:04 am
by GaCop
RAMOS wrote:WJ,

Very nicely put. Especially like the reference to a "pressure bearing". Chasing the lands on a factory 204R is physically impossible anyway. COAL should be accuracy driven, the proof should be on the paper.

Jon
+1!