BARREL LENGTH?

[kenbrofox]

My rem.M7 .243 has a 26" barrel which seems clumsy in the woods, especially so with a mod erator on the end. I would like to cut it to 20". Does anyone have experience of 20" barrels on 243s. I would like to know what the approximate drop would be at 200 and 300yds when zeroed 1 1/2" high @ 100yds. Bullet of choice 70gr. TIA,Ken.

[Wrangler John]

Ken, 20" is mighty short. I had a Remington 40X 27.25" .22-250 barrel cut to 20" once - big mistake. If I were to do it again, I'd have it cut to 24" and see how I liked it and how velocities are effected. Then if it didn't work, I'd go to 22" and leave it there. That 40X action has a 24" .22-250 barrel on it now.

If the average velocity loss is 50 to 75 fps per inch of barrel removed, you'll loose 300 - 450 fps going from 26" to 20". My 6mm Remington barrel is 24", while my .243 Win Super Short Magnum is 26".

The best way to dope out drop is to chronograph your loads and use a ballistic table to estimate downrange performance, or shoot the rifle at each range - this is the best method, on a still day of course.

[kenbrofox]

Wrangler,
This model 7 wore a 20" barrel when it was a 22/250 and was real handy when travelling in a truck to different parts of the estate. Now it's a 243 pacnor it's not so handy.I was hoping someone might have the actual figures because i'm a bit lazy, and it would mean a trip to the 'smith each time i wanted to chop off a bit of barrel. I think i'll take your advice and tread with care rather than one cut too far. I could saw one inch at a time off and chrono,and when velocity is about right have the smith re-crown it. Thanks for your reply.Ken.

[Fred_C_Dobbs]

I have a .243 WSSM with a 22" 1:10 barrel. I'm planning on replacing it with a 20" 1:9 aftermarket barrel. According to QuickLoad, the 2" shorter barrel will cost my 100-grain deer load about 50 fps but it probably will be a tad more accurate.

Just for giggles, I changed it to .243 Win and a 70-gr pill. With a near-max pressure load, QL says going from 26" to 20" will cost you about 230 fps, from about ~3600 back to ~3370 fps.

[Ryan S Albright]

For almost 25 years I used a Ruger M77 in .243 with a heavy 18 inch barrel I bought it used I don't know any history on it. It was glass bedded and shot like a dream I had just changed the trigger out to a timney and loaded it with 65gr Vmax bullets before I sold it to a friend a few months ago. The .243 is a great gun to reload for it is very forgiving. I used to shoot squirrels with and also hunted deer the short barrel made it handy even though it was a heavy barrel. I won a few shooting contest with it also. I had people at the contest ragging about the barrel being too short and the loads I shot being the wong powder but I came is first. I found a picture at the time I had landed a very large scope on the rifle but removed it soon after for years I used a 3x9 Leupold.

[kenbrofox]

Ryan,
I like rifles that look like that, really short. However, I use a moderator all the time,so even with a 20" barrel i end up with 22 1/2" overall,and naff looking to boot.
Fred_C_Dobbs, I fired 3 rounds of federal 100g factory ammo over the chrony today, average..2865, with the 55g B tips factory federal showing 3890 average. Both a bit slower than federals figures. I'll use those as a starting point and start to chop the barrel inch by inch.
Thanks for giggling your QL for the 70gr. Ideally, i'd like a 20" barrel,70gr bullet, zeroed @ 50yds and 200yds and around +1" @ 100yds. I live in hope. Thanks to both of you,Ken.

[Fred_C_Dobbs]

...Thanks for giggling your QL for the 70gr. Ideally, i'd like a 20" barrel,70gr bullet, zeroed @ 50yds and 200yds and around +1" @ 100yds. I live in hope. Thanks to both of you,Ken.

Glad to help.

QuickTarget says a 70gr SMK [1505] will need 3600 fps to be +1.0" @100 and +0.1" @50 with a 200 yard zero. It should stay supersonic to about 850 yards. QT predicts 3370 fps MV with a 200 yard zero will have you +0.3" @50, +1.2" @100 and SS out to 800.

At 3890 fps, your 55gr Nosler BT should be -0.1"@50, +0.7@100.
It predicts that at 3680 fps, the 55 should be spot-on @50 & @200 and +0.9" @100.

**All figured with 1.5" HoB**

[kenbrofox]

Fred,what can i say? Exactly what i wanted. Thanks for taking the time.Ken. PS. No doubt those figures are of interest to some other members also.