Bizzare bullet behavior 22-250


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Mountainman1888
January 27, 2012, 02:02 PM
Hey gents
I have been working on developing a load for my Remington 700 22-250. It has a 1:14 twist in a 26 inch factory varmint barrel. All my loading was based on my results at 100 yards. I was happy with what I had and then went to the 200 line. My groups went from less than on inch to five inches!!?! No signs of key holed bullets, no change in shooting style, no change in wind, weather or ammo. No scope issues either. I loaded 55 grain hornady fmj bt with 37 grainsreloader 15 and a CCI primer. Bullet just off the lands. Any ideas? Could it destabilize after 100? Doesn't make sense and I've been shooting a long time

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Gtscotty
January 27, 2012, 02:27 PM
I'm sure you have these bases covered, but are you using a scope of sufficient magnification?

Is 1:14 a bit on the slow side for 55 gr bullets? I thought most 22-250s had a 1:12 twist... If so, maybe your bullets are under-spun and they are going unstable somewhere between 100 and 200 yds?

Mountainman1888
January 27, 2012, 02:33 PM
Scope has 16 x magnification so it's not that. All Remington 700 22-250 factory rifles (to my knowledge) have the same 1:14 twist. I know 60 grain is too heavy but i think 55 is ok.

rcmodel
January 27, 2012, 02:44 PM
fmj btThat right there is your problem.
Buy some decent bullets with the jacket hole in the front, not the back.

I highly recommend Hornady V-Max or Nosler Ballistic Tip.

Your 1-14" 22-250 barrel will handle up to 60 grain flat base spitzer, or 63 grain Sierra semi-pointed just fine.

Here is the differance between Win FMJ-BT and Nosler BT at 100 yards.
http://i81.photobucket.com/albums/j219/rcmodel/KTOG/EoTecGroup.jpg

The other thing I noticed is, your 37.0 grain load is 1.5 over MAX with a 55 grain V-Max according to Lyman #49.
And 1.7 over MAX with your FMJ-BT according to Hornady #6.

Might want to back off the load, and start over again with better bullets.

rc

Six-Gun
January 27, 2012, 02:52 PM
What rcmodel said ^^

Get yourself some Hornady V-maxes and watch that gun work magic out to much further distances. I use the 55gr. with a 1:14 twist with no issues, and this in on a rilfe designed specifically to snuff prarie dogs at long range.

Mountainman1888
January 27, 2012, 02:56 PM
Right on I will make the changes. However, I'm still perplexed by the fact that there was a 500 percent change in accuracy AFTER the 100 line. It should be terrible at 100 as well, but it's actually under an inch. How can the trajectory violently change direction like that. Jacket does not seem to be separating. Clean holes in the paper. I even drew the trajectory on paper. It dosnt make sense to me. If it opened to 200 or even 300 percent larger at 200 I would be more accepting.

JohnM
January 27, 2012, 03:01 PM
As above. Change bullets.
I usually use 50grn Hornady V-max, mainly because they're cheaper than the Noslers.
My Remington 700BDL varmint has a 24 inch barrel, I didn't know they made it with a 26".
I have a 26" barrel on my 220 Swift, but it's a Ruger M-77.

redneck2
January 27, 2012, 03:37 PM
I suspect it's not the weight of the bullet, it's the length. I'd guess they're slowing down enough that they start to wobble. The longer a bullet is, the harder it is to stabilize, so it needs a faster twist. Stabilization is a function of both twist and speed.

There's a reason most BR bullets are flat based.

Dr T
January 27, 2012, 04:46 PM
Sounds like your bullets are spinning themselves apart. I can't imagine why: They are only spinning at about 245,000 rpm...

NG VI
January 27, 2012, 05:15 PM
If the holes are perfectly clean and hitting paper at 200 yards, where would they be spinning themselves apart?

HOOfan_1
January 27, 2012, 05:19 PM
My .22-250 likes the 50gr. Sierra Blitz King better than the 55gr. V-Max

Blackrock
January 27, 2012, 05:22 PM
I haven't had any luck with FMJ BT bullets in either of my 22-250's. About the same results as you are having. But they both shoot Hornady 55g Vmax's real well.

rcmodel
January 27, 2012, 05:26 PM
If the holes are perfectly clean and hitting paper at 200 yardsNo bullet is perfectly stable at all ranges. Especially for the first couple hundred yards.

Most start out with a slight wobble, then get stable after a certain range, then may wobble again before stabilizing again.

Kind of like a spinning top when you wind it up and toss it on the floor.

You can watch them do it through a spotting scope when laying behind a high-power rifle shooter on the range.

Not saying this is what is happening to your FMJ, but it might be.

rc

NG VI
January 27, 2012, 06:03 PM
Right, but isn't one of the hallmarks of a bullet that's been spun to destruction that they are no longer coherent bullets capable of leaving clean holes and flying remotely normal trajectories?

rcmodel
January 27, 2012, 06:14 PM
You are not spinning them apart.

The 55 FMJ is a tough bullet and will stay together in a 1/7" AR barrel.
.223 @ 3,200 FPS in 1-7" = 256,000 RPM.
22-250 @ 3,800 FPS in 1-14" = 195,429 RPM.

rc

NCsmitty
January 27, 2012, 06:30 PM
My guess, and most posters are doing just that, is the FMJ doesn't have as well balanced core as do the V-Max or even the good old flat base match bullets. It's possible that the stability is affected on the way to the target by tiny core differences.
Just try some V-Max or Nosler BT and you'll probably see a positive difference, if you're doing your part at the bench.

Remember those FMJBT are turned out by the millions, and are not match type bullets.


NCsmitty

Damon555
January 27, 2012, 07:05 PM
Bullets, bullets, bullets.....Get some good, name brand bullets and watch that 22-250 shine.

GooseGestapo
January 27, 2012, 08:05 PM
It's the bullets. Seen it many times before, especially with FMJ's.

My older brother was on the U.S.Airforce Sec.Police team at McDill,AFB in the late '70's. They had some of the first match accurized M16's turned out from the USAF armory at Lackland,AFB. These were the first to have free-float tubes.

My brother was one of several individuals tasked with testing an assortment of different lot#s of ammo for use by the team in competiton.

I watched one afternoon as he demo'd some different ammo for the officer in charge of the operation/program.
One lot# of LC-75 ammo shot decent 1.5" groups from a sand-bagged M16 at 100meters. He then directed it at the 300yd target. Watching through the spotting scope, you could see the bullets destabilizing before the 300yd target and look like buckshot patterns of 10-12". The bullets were unbalanced and were diverging in a random pattern.

Another lot# from LC-72 IIRC, drove tacks at 300meters. Around 4" groups for 10shots was the norm, but the 100meter groups appeared the same 1.5".
An entire 18wheeler load of that ammo was sent to Lackland AFB and disbursed throughout the USAF teams. They kicked butt at the Nato World shoot that year. My older brother took 11th.

I've seen similar results with differnent lot#'s of non-fmj bullets too. Particularily Hornady bullets. Explains the occasional lot#'s of "blems" available that otherwise appear "normal"....but at "bargain" prices...

guntech59
January 27, 2012, 11:14 PM
What rcmodel said ^^

Get yourself some Hornady V-maxes and watch that gun work magic out to much further distances. I use the 55gr. with a 1:14 twist with no issues, and this in on a rilfe designed specifically to snuff prarie dogs at long range.
What he said......Savage 110, 22-250. 10 power scope. 50gr or 55gr VMAX or Sierra 55gr HPBT. Most FMJ bullets are NOT going to give you the best accuracy.

http://i33.photobucket.com/albums/d86/guntech59/224064-5.jpg

http://i33.photobucket.com/albums/d86/guntech59/22-250bestgroup.jpg

helotaxi
January 27, 2012, 11:45 PM
I suspect it's not the weight of the bullet, it's the length. I'd guess they're slowing down enough that they start to wobble. The longer a bullet is, the harder it is to stabilize, so it needs a faster twist. Stabilization is a function of both twist and speed.

There's a reason most BR bullets are flat based.
Bullets actually get more stable as they slow down. The only reason that speed matters is to impart the initial spin. The aerodynamic forces on the bullet are proportional to its velocity through the air. These forces are in front of the CG of the bullet and try to upset it. That and the geometry of the bullet are what the spin is fighting against for stability. The geometry is constant, the aero forces are not. The spin on the bullet is relatively constant as it goes down range and if it is enough to stabilize the bullet out of the barrel, it will be more than enough once the aerodynamic upset force decreases as the velocity decreases with range.

The only time you have to worry about bullets losing stability as they go downrange is when you have a bullet that have problems with transonic stability and the bullet slows down into the transonic region. You might get a dynamic wobble, but that is different from going unstable. The inconsistent bases of the typical FMJ bullet lends itself to this type of problem. Not to mention that the inconsistent base also means that they have a tendency to spray a bit from the muzzle as the gases come out from around the base of the bullet unevenly. That will impart a good bit of wobble as well.

ETA: BR bullets are flat based mostly because FB bullets are usually more consistent in the heel area. There is one less step in the manufacturing process so one less step to introduce inconsistency. The BR guys also don't care much about BC so gain no benefit from a boat tail.

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