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Old January 25, 2013, 11:59 AM   #1
Mr. Whimsy
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30-06 18.5" chrono data?

There is a new Rem. 7600 18.5" carbine I have my eye on. I would rather it came in .260, but no one listens to me. Anyway, I think I can put a Choate youth shotgun pistol-grip buttstock on this rifle and have a very handy carbine. I may or may not reduce my loads for it depending on the recoil.

So, owners of 7600 carbines in 30-06: what velocities are you getting?

Also, is there a faster 30-06 powder more suitable for 18.5"?

BTW I have already heard the rumors of "200 fps velocity loss" and pretty skeptical. I hunted with a 16.5" Mini 14 and the velocity loss had no effect whatsoever on the deer I shot, so it is merely for academic purposes that I want to know.
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Old January 25, 2013, 01:01 PM   #2
jmr40
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I've never worked with anything shorter than 20". Expect an average of 25 fps loss for each inch shorter. Most factory ballistics are from 24" barrels, so 100-150 fps slower than advertised on factory loads.

It is impossible to say for sure because every load and barrel is going to be different. I load for 7 different 30-06 rifle, 2 have 20" barrels. Depending on the load the 20" guns are 50-75 fps slower than the 22" and 24" barrels. The fastest barrel is one with 22" barrel that shoots the same ammo faster than the one with a 24" barrel. There is a 135 fps difference between the fastest 22" barrel and the slowest 22"barrel.

Quote:
Also, is there a faster 30-06 powder more suitable for 18.5"?
This is a myth. If you hand load, which ever powder gives the best speed in a longer barrel, will still give you the best speeds in a shorter barrel. I'm using H-4350. From my 20" guns my handloads are still faster than factory specs for a 24" gun and much faster than a 308 loads from 24" guns. You will get more muzzle blast. It is not that bad from a 20" gun. Another 1.5" less, I can't say. But as far as perfomance on game. You will still probably beat 308 specs and that ain't a bad thing.
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Old January 25, 2013, 01:46 PM   #3
Hummer70
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I agree 260 in a 7600 would be a game winner. I used to have a 18" barrel 742 and the muzzle blast from that sucker was horrible to say the least. At this time I have a Rem 7615 with 16" barrel and in daylight I get a 12" fireball from all the unburned propellant igniting after it does any good.
Without having the noise signature evaluation equipment I had at Aberdeen PG it is a guess but from a perceived noise standpoint the 762 30.06 and the 7615 5.56 is pretty close.

They call it a Police Patrol Rifle and I ordered it with a Youth Stock as I like stocks shorter than 12" They were made short so the rifle could be fired by personnel with body armor. The 7615 has put four out of five rounds in a 2" dot at 300 yards on several occasions.

A loss of 200 fps from 22" down to 18" is about right based on the chronograph readings I have done. I have seen as much as a 400 fps increase in velocity on 357 Mag ammo from 3" to 16" barrel.

I think all things being considered I would tend to gravitate towards a 7600 in 308 and install a Aimtech mount which I have on my 7615 and rapid close in shots are much quicker based on my R U Ready Timer.

http://www.aimtech-mounts.com/

If I were going to a speed/accuracy match this is the combo I would take.

My 7615 also has a Burris Ballistic Plex Scope and is zeroed at 300 yards.

Such timers can give you lots of good tech info regarding time to engage a target from the go beep to the shot being fired. A good course of fire from Fr. Frog's pages uses 6" paper plates at 25 yards and you are timed for X number of 1 shot strings and then a count is made of the hits on the plate as the course is designed to determine speed and accuracy. Speed without accuracy gives misses, accuracy without speed may well get you tagged first.

They also do the same procedure on 6" plates at 50 yards.

As well short barreled rifles burning lots of propellant tend to erode the crown which will open your groups. Rifles exhibiting longer barrels have less muzzle pressure and the barrel should give you a longer useful life.j

As well the barrels from 7600s can be removed and the crown touched up several times many rounds down the road.
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Old January 25, 2013, 03:21 PM   #4
Mr. Whimsy
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Thanks guys.

The Patrol rifle in .308 is no longer being made as far as I can tell, or I'd just get that. No body armor here, but I do get padded up with warm clothes during deer season so the short stock is desired, as well as avoiding the stupid uncomfortable comb they put on the standard buttstock. Does anybody like that thing?

I have grown accustomed to the noise from my 16" .223's, so doubt the short barrel would bother me. My coping strategy is to put on ear protection before taking a shot on a deer, even with longer barreled guns.
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Old January 25, 2013, 03:22 PM   #5
Mr. Whimsy
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Also, fascinating info on timed courses of fire there.
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Old January 26, 2013, 10:51 AM   #6
Hummer70
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Iforgot to add I took the 742 Carbine to a rifle match once and it was picking up trash three feet each slide of the muzzle while shooting prone and guys nearby said they were being rocked when it barked. Short barrels can be handy but you may lose your hearing much quicker.

I always shoot highpower with foam plug and muffs to protect hearing.

Was out walking with my dog about a month back and this big German Sheppard came up and started circling with head down and I maintained eye contact as it circled. I had a shorty AR and thought about giving a warning shot so I pulled the charging handle and chambered one and fortunately the Sheppard figured out the game was going to go South quick and backed off.

I was ready to fire and then realized I had no ear protection and was real glad when the sheppard left us alone.
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