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JBLEDSO, the recoil idea is something I haven't considered but the logic works. Interesting.
When a country is well governed, poverty and a mean condition are something to be ashamed of. When a country is ill governed, riches and honors are something to be ashamed of
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I will bet one BoreSnake (new) in 12-gauge size that there is no appreciable difference. HA HA- - that word "appreciable" is so ripe for lawyer interpretation Rocky. Heck, have you seen the hairs we split around here at times? I can just hear it, if the difference is 100fps someone would say, "well if I threw a 165 grain bullet at you at 100 fps I bet you would call it mighty appreciable upon impact?" and maybe follow that with the old "nuff said" to punctuate. Unlike my friend, who asks an intelligent if unenlightened question, I don't see anyone here saying the difference will be noticeable, just wondering if it exists and if so- how measurable.
When a country is well governed, poverty and a mean condition are something to be ashamed of. When a country is ill governed, riches and honors are something to be ashamed of
. Confucius
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Campfire 'Bwana
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I have all the respect in the world for Rocky's expertise. That being said, I have compared Browning BAR's in 25-06 and 280 to bolt guns by shooting the same the loads side by side over a chrony.
Chrony said the BAR was shooting the same loads ~ 200 fps slower.
I believe Browning has publicly admitted the same.
Of course the 200 fps only matters to the chrony. Neither the operator nor the intended critter will notice a practical difference without reading the chrony.
GE My results are the same as yours, every time that I have chronographed a semi auto of the same caliber and barrel lenght as one of my bolt actioned rifles the velocity has always benn lower in the semi auto... by as much as 200 FPS..
I got banned on another web site for a debate that happened on this site. That's a first
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Campfire Tracker
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All due respect...but run both typs of guns over a crony...bolt .22 and semi .22. I did this a few years back just for fun. The semi was slower by about 65 fps. Just my guns?? Maybe we need someone to test accuratly and report back??
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Campfire Member
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I have all the respect in the world for Rocky's expertise. That being said, I have compared Browning BAR's in 25-06 and 280 to bolt guns by shooting the same the loads side by side over a chrony.
Chrony said the BAR was shooting the same loads ~ 200 fps slower.
I believe Browning has publicly admitted the same.
Of course the 200 fps only matters to the chrony. Neither the operator nor the intended critter will notice a practical difference without reading the chrony.
GE My results are the same as yours, every time that I have chronographed a semi auto of the same caliber and barrel lenght as one of my bolt actioned rifles the velocity has always benn lower in the semi auto... by as much as 200 FPS.. A lot a semi's have chambers that are even sloppier than factory bolt guns, and therein lays your difference. I've seen 270+fps difference between chambers, and they were both cut in the same barrel, mounted on the same receiver, and using the same lot of handloads. At 26" with a oversize throat the ammo was chron'ed at 2725, at 25" with a tight throat the same ammo chron'ed at 2995
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Campfire 'Bwana
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Campfire 'Bwana
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My Ruger Mini-30 has a custom ASI barrel chambered in 7.62x39 with a .308 dia bore. I fired identical rounds with the gas port wide open and then completely closed. Same action,same barrel, same chamber and same rounds.
This is what I came up with. Temp 22*, wind 18 MPH and damn cold.
AA 2230 125gr Sierra PH.
Open GP 2107
2081
2102
2095
2098
2102
2098
2093
2096
2079
Avg 2095fps
GB Closed 2118
2107
2095
2095
2119
2120
2121
2106
2090
2086
Avg 2106fps
R-7 125gr Sierra PH.
Open GB
2434
2392
2396
2389
2388
2418
2413
2383
2412
2415
Avg fps 2404
GB Closed
2400
2405
2434
2430
2418
2397
2438
2440
2430
2423
AVG 2421fps
H322 110gr VMax
Open GP 2318
2340
2324
2321
2308
AVG 2322fps
Closed GP
2337
2345
2329
2348
2321
AVG 2336fps
H322 125gr Sierra PH
Open GB
2297
2300
2303
2306
2256
AVG 2294fps
GB Closed
2292
2300
2291
2322
2326
AVG 2306fps.
By my rough calculations the closed gas port has an increased velocity of about 15fps in this little round. Kinda like pissing in the Ocean as far as the 7.62x39 is concerned.
That's about .65% increase in velocity. With a 3000fps round that would be about 20fps.
Last edited by steve4102; 03/21/08.
Give a man a fish and he eats for a day. Give a man a welfare check, a forty ounce malt liquor, a crack pipe, an Obama phone, free health insurance. and some Air Jordan's and he votes Democrat for a lifetime.
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Campfire 'Bwana
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Campfire 'Bwana
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And it's also less than some of the round-to-round variation in a given string. Verdict: no change.
Cleverly disguised as a responsible adult.
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Campfire 'Bwana
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Does that mean I don't get the Bore-Snake?? Ah, Crud.
Give a man a fish and he eats for a day. Give a man a welfare check, a forty ounce malt liquor, a crack pipe, an Obama phone, free health insurance. and some Air Jordan's and he votes Democrat for a lifetime.
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Campfire 'Bwana
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I didn't hear a counter-bet, Steve. But if you want the durn thing, I'll send it to ya.
Cleverly disguised as a responsible adult.
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Campfire 'Bwana
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Campfire 'Bwana
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Give a man a fish and he eats for a day. Give a man a welfare check, a forty ounce malt liquor, a crack pipe, an Obama phone, free health insurance. and some Air Jordan's and he votes Democrat for a lifetime.
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Steve, I forgot to thank you for providing the excellent scientific info. Commendably done. I forwarded your findings along with my note that the differences seemed to be more or less within standard deviation of a single load. My friend is funny about it. We weren't arguing over this, merely conjecturing, but he is tenacious and his response was to note that the difference definitely was measurable, (which seemed a far cry from his original supposition) - so he kind of felt he was "right" so to speak. I sent him a note back chiding him that if his wife had argued his position on this subject he would scoff and say something like, "Yeah, its measurable. About as measurable as a fart in a hot air balloon". CC'd a mutual friend who got a good chuckle over that. Thanks again. Great stats, made the conversation very satisfying.
When a country is well governed, poverty and a mean condition are something to be ashamed of. When a country is ill governed, riches and honors are something to be ashamed of
. Confucius
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Campfire 'Bwana
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Campfire 'Bwana
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Give a man a fish and he eats for a day. Give a man a welfare check, a forty ounce malt liquor, a crack pipe, an Obama phone, free health insurance. and some Air Jordan's and he votes Democrat for a lifetime.
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Campfire 'Bwana
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As I posted earlier I have never chronographed a Semi Auto that wasas fast as a bolt even when useing the same ammo on the same day.I assumed from this that the semiautos action was the culprit, but after reading Steve's results this was a faulty assumption...
I got banned on another web site for a debate that happened on this site. That's a first
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