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Noel
October 16, 1998, 03:02 PM
223 Barrel Length changes
<TABLE><TR><TD VALIGN="TOP">Length</TD><TD VALIGN="TOP">Win. 55 FMJ
Velocity</TD><TD VALIGN="TOP">Mil 62
Velocity</TD><TD VALIGN="TOP">Win 55 FMJ
Energy</TD><TD VALIGN="TOP">Mil 62
Energy</TD></TR><TR><TD VALIGN="TOP">10</TD><TD VALIGN="TOP">2739</TD><TD VALIGN="TOP">2627</TD><TD VALIGN="TOP">916</TD><TD VALIGN="TOP">950</TD></TR><TR><TD VALIGN="TOP">11.5</TD><TD VALIGN="TOP">2872</TD><TD VALIGN="TOP">2738</TD><TD VALIGN="TOP">1007</TD><TD VALIGN="TOP">1032</TD></TR><TR><TD VALIGN="TOP">14.5</TD><TD VALIGN="TOP">3064</TD><TD VALIGN="TOP">2907</TD><TD VALIGN="TOP">1146</TD><TD VALIGN="TOP">1163</TD></TR><TR><TD VALIGN="TOP">16</TD><TD VALIGN="TOP">3112</TD><TD VALIGN="TOP">2989</TD><TD VALIGN="TOP">1198</TD><TD VALIGN="TOP">1230</TD></TR><TR><TD VALIGN="TOP">20</TD><TD VALIGN="TOP">3529</TD><TD VALIGN="TOP">3095</TD><TD VALIGN="TOP">1297</TD><TD VALIGN="TOP">1318</TD></TR><TR><TD VALIGN="TOP">24</TD><TD VALIGN="TOP">3315</TD><TD VALIGN="TOP">3158</TD><TD VALIGN="TOP">1342</TD><TD VALIGN="TOP">1373<TD></TR><TR><TD VALIGN="TOP">26</TD><TD VALIGN="TOP">3391</TD><TD VALIGN="TOP">3231</TD><TD VALIGN="TOP">1404</TD><TD VALIGN="TOP">1437</TD></TR></TABLE>3 5 shot groups from 3 rifles 0 degrees F RH 20%

[This message has been edited by Zach (edited 10-17-98).]

.
October 17, 1998, 01:43 PM
Noel,

This looks like good test data.

Would you please append the source for future reference and identification? I'd like to add this as an accretion to the data reef.

Also, it appears there is a typo in the data field for 55-grain velocity at the 20" length barrel. Please double check that.

Thanx,
Mykl



[This message has been edited by Mykl (edited 10-18-98).]

Noel
October 18, 1998, 11:08 PM
Mykl,

I have been searching through all my crap for the 2 articles I have had in my possesion in the past on barrel length. I had a paper copy of this that did not have a reference just a mention of the Bushmaster web site.

I agree that a typo is likley I plotted this data and that point is a outlier. I believe 3259 is correct ??

Noel

Noel
October 18, 1998, 11:11 PM
Mykl,

Do you have any contacts with people that could search for similar data for .308 and 30-06??

It has been published in the past, I've lost it.

I'm considering cutting off 2 of my rifles to 18 or 19 inches. I also want to mount reserve ghost ring sites. Any suggestions on that??

Thanks,

Noel

fal308
October 19, 1998, 08:48 AM
Depending on the weapon, be careful on how much you cut off as you can affect the gas operation. The pressure could drop off too quickly and your piston could shortstroke.

.
October 19, 1998, 09:28 AM
Noel,

That would certainly be more commensurate with the KE value. I'll check the USAOPTEC Tech Library and with a couple of ORSAs that have been in the wpns testing business since dirt was new. I'll also ck w/ DOTE for any historical database of which they're aware. Back to you in a day or two.

FAL308,
You're right about the non-adjustable gas guns, however it can also affect recoil operated guns, when the barrel is so short that a significant portion of the fire column exits the bore. Sometimes changing the bullet wt and powder with a faster burn rates can make the short barrel more practical.

.
October 19, 1998, 09:31 AM
Noel,

Sorry, but I've no personal experience with reducing barrel lengths on civilian rifles, only on pistols. I'd recommend you pose this question to the guys in the 'Smithy forum.

chris93473
September 10, 2002, 06:26 PM
"longer barrels makes more velocity"...i think

Southern Raider
September 11, 2002, 05:15 AM
Here's a table from Bushmaster:

http://www.bushmaster.com/images/faqchart.gif

artech
September 11, 2002, 06:17 AM
Yep, we got bored that winter and decided to do some shooting. Assembling that data was a real PITA, so I'm glad people can get some use out of it.:D