243 optimization in short barrel


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stubbicatt
October 21, 2012, 09:04 PM
Guys, I have a 20" 243 barrel. I know that it will be somewhat handicapped in terms of velocity over a standard length 24 or 26" barrel. Due to excessive laziness just now, and no particular desire to deploy the CED chronograph to verify my suspicions, I have two somewhat interrelated questions.

1) Since the tube is shorter, will I see any improvement in velocity given an 80 grain bullet by using 4350 over say RL15? I guess in my mind the slower powder would still be burning upon bullet exit where the faster RL15 would be totally consumed in that barrel length.

2) Given whatever velocity handicap I have imposed on myself with the shorter barrel, would I do better to choose heavier bullets for my applications in effort to retain trajectory and downrange energy? --Ferinstance, a 55 grain bullet at some of the velocities I see published is really attractive to me to the reasonable distance of 300 yards, but am concerned that any energy gains due to the hyper velocities possible in this combination (E=MxV^2) may be lost due to the shorter tube. Would retained energy due to velocity be more than offset by use of a heavier projectile in a shorter barrel?

Not so sure my posting is clear, but I hope you guys get the gist of it.

Regards,
Stubb.

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R.W.Dale
October 21, 2012, 09:31 PM
The fastest load will be the fastest load reguardless of bbl length. Guns are not rockets they don't burn propellant as the bullet travels down the entire length of the bbl. In fact all the powder that will burn will have done so before the bullet makes it just a few inches down the bbl.

Typically the more overbore the case the more shortened barrels hamper velocity. The 243 being one of the most overbore really gets hammered


Bullet performance for the intended use is what matters if expansion and penatration is there energy means nothing. For example a 55g 6mm bullet at any speed is wholly unsuitable for any critter bigger than rodents



posted via that mobile app with the sig lines everyone complaints about

41 Mag
October 22, 2012, 06:34 AM
I have been shooting a 20" barreled .243 since I was 6 which is now some 40+ years. In all that time I was never worried about what velocity I "gave up" to a longer barrel. I worried more about the accuracy of the rounds which went downrange.

I also have never been much of a fan for bullet weights in this particular caliber which were under 85grs. While you can get some screaming loads using the lighter ones, their weight simply doesn't do the added wear and tear on your barrel any justice. With the mid to heavier weights you gain downrange energy the further you go over the lighter pills as the velocity starts to fall off quicker.

You didn't mention what your intended uses were, but with today's huge selection of bullets from different manufacturers, you could use an 85gr bullet that would have a violent explosive impact for varmints, and also have one in something like the Partition to use for hunting medium sized deer. I personally used the 85gr Nosler Solid Base for years until they discontinued it, then I switched to using the 95 and 100gr bullets.

There have been VERY FEW times I felt handicapped with either of the latter weights within the ranges I normally hunt. If the load is accurate, and you put it where it needs to go, you WILL have meat on the ground to deal with.

The biggest problem I see with the lighter weight bullets is the wind works them over pretty hard when the ranges start to get on out there. Not to say it doesn't move the others around, but they do hold their own a bit more consistently.

Birdhunter1
October 22, 2012, 04:19 PM
Stubby a combination of 50.4 grains of VihtaVuori N560 using a Federal 210M primer and an 87 grain Hornady Vmax using a 22" barrel on my Tikka T3 stainless laminated gives me an average speed of 3380 fps.

Sounds high and it is, but 3 different chronographs have measured an average of 9 shots at 3380 fps. Hope this helps

helotaxi
October 22, 2012, 10:52 PM
For example a 55g 6mm bullet at any speed is wholly unsuitable for any critter bigger than rodents They're pretty stern medicine for coyotes...

Bullet construction is just as, if not more, important than weight, regardless of velocity and energy and all the rest. A 105gn varmint bullet is still unsuitable for deer while a 70gn controlled expansion bullet will get the job done.

Ridgerunner665
October 22, 2012, 10:57 PM
I get 2,950 fps from an 80 grain Nosler Ballistic Tip from my 20" 243...using 44 grains of H4350.

You can still get good speed form bullets weighing 85 grains or less...above that, it goes downhill fast.

I've never used a bullet lighter than 70 grains (3,300 fps) in my 243...I like the Sierra BlitzKings.

Snag
October 22, 2012, 11:59 PM
Seems like your worrying way too much about having a 20" barrel. My M77 is a lightweight model with a 20" barrel. Every load I've chronographed was within 100 fps of published data, I use Sierra and their test barrel was 22".

murf
October 23, 2012, 01:55 AM
generally, a faster powder will give better results in a shorter barrel. but, not much. suggest you use what is most accurate in your rifle.

murf

FiveInADime
October 23, 2012, 06:49 PM
To to OP:

I have good results with H4350 with all the bullets I use in my 22" barreled Winchester M70 .243

I use 87 Grain V-Max, 85 Grain Sierra HPBT, and 70 Grain Nosler BT's

I don't push the Max on any of them really. The H4350 does give me considerable muzzle blast compared to factory loads and loads with powders such as Varget and 4064 (RL15 would probably be about the same) but I get better accuracy with the H4350. I think that might be due to better case-fill.

jmr40
October 23, 2012, 09:19 PM
generally, a faster powder will give better results in a shorter barrel. but, not much. suggest you use what is most accurate in your rifle.

murf

This is a myth. It is easy to believe and seems to make sense, but if you find the fastest load from a long barrel, that will also be the fastest load from a shorter barrel. Which will usually be a slower burning powder.

You will see better results with heavier bullets at longer ranges. The heaver bullets are going to be more aerodynamic and that will offset the slower speed better than trying to push a lighter, less aerodynamic bullet faster.

I'd be looking at 100 gr+ bullets.

This is what a 105 gr VLD bullet will do at almost 700 yards. It is a lot slower at that range than your 20" gun will be at "normal" ranges.

http://www.youtube.com/watch?v=hY0w1c-gf18

AABEN
October 23, 2012, 10:37 PM
Guys, I have a 20" 243 barrel. I know that it will be somewhat handicapped in terms of velocity over a standard length 24 or 26" barrel. Due to excessive laziness just now, and no particular desire to deploy the CED chronograph to verify my suspicions, I have two somewhat interrelated questions.

1) Since the tube is shorter, will I see any improvement in velocity given an 80 grain bullet by using 4350 over say RL15? I guess in my mind the slower powder would still be burning upon bullet exit where the faster RL15 would be totally consumed in that barrel length.

2) Given whatever velocity handicap I have imposed on myself with the shorter barrel, would I do better to choose heavier bullets for my applications in effort to retain trajectory and downrange energy? --Ferinstance, a 55 grain bullet at some of the velocities I see published is really attractive to me to the reasonable distance of 300 yards, but am concerned that any energy gains due to the hyper velocities possible in this combination (E=MxV^2) may be lost due to the shorter tube. Would retained energy due to velocity be more than offset by use of a heavier projectile in a shorter barrel?

Not so sure my posting is clear, but I hope you guys get the gist of it.

Regards,
Stubb.
You are worried over nothing use some 4350 and you will be good to go.

kingmt
October 26, 2012, 03:25 PM
There is so much more to it then just grabbing a bullet, powder, & away you go.

I spent most of a year making a 65 gn V-Max a perfect deer load. First it can't be pushed to fast for its jacket construction. You have to have it fast enough to stabilize.

Faster doesn't mean more penetration. The opposite is the norm.

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