22 cal Tipped MatchKings 69 gr. From 22-250

[mike22250]

I have a question reguarding bullet stabilizing in my 22-250 with a 10 twist.
Bulleta are sierra 22 cal. 69 gr. TMK. with H414 powder and Hornady brass, Win LR primers.

I can't get them to stabilize. See attached.

I have shot the 70 gr. VLDs from Berger.

What can i try to get the to stabilize? Speed up velocity? Slow velocity?

Thanks

 

[Texas10]

What was the distance to target and velocity in the above photo? What is the SG value that you calculated and bullet RPM at the muzzle? These numbers will help analyze what is going on. Also, do all impacts from this load leave the identical mark and are you shooting downhill to any substantial degree?

 

[mike22250]

I have not any number crunching..... loaded up 3 different powders. Shot groups. And then loaded up more of the best group.

No velocity check.

Just saw 10 twist on box and price was right so i purchased a box.

I just switched the barrel to a new action and stock. I have a Bergara rem-age barrel.

 

[mike22250]

Ok so i looked in my reloading log and it is 38.6 gr. Of H414 to a 2.466 OAL. Distance was 100 yards in flat land. Temp was in the mid 30s.....

 

[mike22250]

The books est. Velocity is 3250 fps

 

[Brians356]

Of the 69-gr TMK, Sierra only state "This bullet requires a barrel twist rate of 1:10 or faster".

For a given bullet and twist rate, increasing velocity should improve stability, assuming the jacket remains intact.

PS you might measure the actual twist rate of the barrel, just for grins. It just could be 10.x and so more marginal with that bullet than assumed.
-

 

[fyrewall]

Measure everything,

Measure the length of the bullet, then subtract the length of the plastic tip. There is some controversy about this - the thinking is that the plastic tip being lighter than the rest of the bullet the center of mass is not affected.

Then

Measure the twist of your rifle barrel. Clean the bore enough so a patch will not grab and jump when passed through the bore - smooth & easy. Tighten a jag onto the end of a cleaning rod with pliers - don't want this turning. Get a roll of masking tape, a felt tip marker & a tape measure. Put a patch on the jag and run it into the bore say about 14-18 inches. Then put a turn of tape on the cleaning rod at a defined spot, say the rear of the bridge on the receiver. Using the felt tip pen draw a line on the top of the tape. Slowly and gently withdraw the cleaning rod watching the line on the tape rotate. When one complete rotation occurs measure the distance from the front edge of the tape to the defined spot. This will give you the twist rate.

The next step is to run some version of the Miller Twist Program - this may be found on line. Input your data - twist rate, length, diameter, weight, approximate velocity, and temperature. The program will provide a Sg value - stability index. This should be somewhat over 1.2. Then run the program using data for other bullets that do stabilize, knowing the twist, bullet weight, diameter, and length and look at their Sg. values. This will give you a sense of the data. The Miller stuff may be found on the Berger site or JBM - calculations - stability. The JBM site provides for plastic tip length.

Upon playing with this stuff observe that temperature is probably the most important non-fixed variable, velocity not as much. Ultimately, how good it shoots will be the deciding factor. Should the Sg program indicate a high degree of stability for a given bullet and stability fails shown by sideways impacts - keep on looking and run everything over. Can't be positive it is a 1-10 until you check it out. If all else fails go for a shorter bullet but check things out using the JBM bullet length site and JBM stability calculator on line before spending $ on bullets.

I like H414 with 68-75 grain bullets in my .22-.250's. I once had a 1-10 twist .250 that shot the 68 Hornady bthp very well and that bullet is probably longer than the Sierra Tipped MK minus the plastic tip. The 69 Sierra Tipped MK is a real good long range varmint bullet and just as effective as many 6mms for that purpose.

 

[thatguyshm]

Being that your Berger 70gr at 0.976" stabilized and the TMK at 0.982" wouldn't, I would look at velocities. (measurements taken from JBM, Berger stability tool states the 70gr at 0.961, just to note) Run both over the chrono at the same time. I can only assume bearing surface difference is giving you different velocities causing your barely marginally stable bullet to not properly stabilize fully.

No matter what, with both bullets you are losing enough BC that I would drop down to a faster, lighter bullet, like maybe the 60gr TMK, on sale at Midway right now.

Edit: as a caveat, I shoot the 69gr TMK with AR Comp in an 8 twist 22-250, and it's explosive and great for predator hunting.

 

[Rdlningcltchdmpr]

Increasing velocity is not the answer according to expert. You would have to increase so much you would not get there in the cartridge being used. Must go to shorter bullet. Like the 69 m.k. with no plastic tip.

 

[fyrewall]

Play around with the stability program and see that velocity has little effect. For example, the 69 Tipped MK .224 Sierra is .982 in. long and has a light plastic tip that is probably .09 to .1 inches long. Running the JBM stability program for that bullet, 69 grains, .224, .982 oal., .09 plastic tip @ 3200 provides a Sg of 1.307. Boosting the velocity to 3500 while keeping the same bullet the Sg now is 1.347. A Sg increase of no consequence. Taking the same bullet but boosting the temperature from 59 degrees F to 100 F the Sg is now 1.411.

Common thinking is light plastic tip has little effect on stability and the JBM bullet stability calculator takes this in account - expert? - yes

Were the 70 VLD's & 69 Si TMK shot at the same temps? The JBM stability program indicates a higher Sg for the 69Si TMK than for the 70 VLD provided the length of the plastic tip is input.

Knowing all this stuff can prevent problems - like buying 500 bullets that will not stabilize in a slow twist rifle. I assume your rifle has a 1-10 twist.

 

[C.E.Smith043]

One thing you might try just to see if it will make a difference is scrub the Daylights out of the barrel and get it really clean. That may expose more of the rifling and help it grab a better hold on the bullet and twist it harder.

One of the problems with this is if it does indeed work you'll have to always keep the barrel clean

 

[mike22250]

Thanks to all. Good info.... lots of smart people in this forum. I will do some testing and post my results in the next couple weeks.

I have a 22-250 that loves the 40 gr. Vmax.... shoots in the low .3's. Im running them just under 4k and they throw parts of the prairie dogs, but suck in the wind. I shoot alot in Wyoming where it is windy.

 

[C.E.Smith043]

Thanks to all. Good info.... lots of smart people in this forum. I will do some testing and post my results in the next couple weeks.

I have a 22-250 that loves the 40 gr. Vmax.... shoots in the low .3's. Im running them just under 4k and they throw parts of the prairie dogs, but suck in the wind. I shoot alot in Wyoming where it is windy.

I havent shot them yet but have heard nothing but good about them, the 53gr Vmax. That might be a great go between for you. Get the higher speeds of the lighter weight bullets but the increased b.c. of the elongated 53gr design.

I would be very tempted to look at the 53gr vmax with Lapua brass and Fed Gold Metal primers with a good stiff load of IMR 4064. Of course work ur load up. But over the 23 years ive been shooting the 22-250, nothing has outperformed IMR 4064 for me in that cartridge.

 

[Rdlningcltchdmpr]

 

[RGRobinett]

For .224 bullets of this length you really need 1:9", or, faster twist rate - when it comes to polymer tipped bullets, the Miller formula is lacking: JBM is far better for calculating Sg which we can,"bank on" - especially for the, "tipped" projectiles. For most HP bullets, specific gravity input of 10.2 will get you close - tipped bullet will run 10.0, or, less (lower specific gravity of construction will require faster twist rate - think aluminum!)

At Std. conditions, these bullets (OP) need 1:8.5" twist for Sg 1.5, or, "sure-fire" stability: 1:9" would probably produce about Sg 1.4. Polymer tipped bullets add substantial length (over-turning moment) without a significant shift in CG.

Mr. Peffley is correct - even if we had "magic" powder, which would produce 4K++ FPS, at safe pressure, we'd only gain a few points in the second decimal place, when we need a nearly two point increase in the FIRST decimal place. The notion of increasing velocity to obtain meaningful Sg increase is simply myth and misinformation. If the combination of TWIST rate and bullet length results in marginal, or, inadequate stability, performance will suffer - especially in denser air. RG

Edited to [somewhat] clarify - AM 3/1.

 

[mike22250]

I havent shot them yet but have heard nothing but good about them, the 53gr Vmax. That might be a great go between for you. Get the higher speeds of the lighter weight bullets but the increased b.c. of the elongated 53gr design.

I would be very tempted to look at the 53gr vmax with Lapua brass and Fed Gold Metal primers with a good stiff load of IMR 4064. Of course work ur load up. But over the 23 years ive been shooting the 22-250, nothing has outperformed IMR 4064 for me in that cartridge.

I love IMR4064 in the 3006. I may have to try that. Thanks.

 

[fyrewall]

I have used the 53 Vmax from 1-7.7 and 1-8 twist rifles and it works well - a 1-12 would probably be best for the .224 53 Vmax - it is long for its weight and real pointy.

 

[mike22250]

Measure everything,

Measure the length of the bullet, then subtract the length of the plastic tip. There is some controversy about this - the thinking is that the plastic tip being lighter than the rest of the bullet the center of mass is not affected.

Then

Measure the twist of your rifle barrel. Clean the bore enough so a patch will not grab and jump when passed through the bore - smooth & easy. Tighten a jag onto the end of a cleaning rod with pliers - don't want this turning. Get a roll of masking tape, a felt tip marker & a tape measure. Put a patch on the jag and run it into the bore say about 14-18 inches. Then put a turn of tape on the cleaning rod at a defined spot, say the rear of the bridge on the receiver. Using the felt tip pen draw a line on the top of the tape. Slowly and gently withdraw the cleaning rod watching the line on the tape rotate. When one complete rotation occurs measure the distance from the front edge of the tape to the defined spot. This will give you the twist rate.

The next step is to run some version of the Miller Twist Program - this may be found on line. Input your data - twist rate, length, diameter, weight, approximate velocity, and temperature. The program will provide a Sg value - stability index. This should be somewhat over 1.2. Then run the program using data for other bullets that do stabilize, knowing the twist, bullet weight, diameter, and length and look at their Sg. values. This will give you a sense of the data. The Miller stuff may be found on the Berger site or JBM - calculations - stability. The JBM site provides for plastic tip length.

Upon playing with this stuff observe that temperature is probably the most important non-fixed variable, velocity not as much. Ultimately, how good it shoots will be the deciding factor. Should the Sg program indicate a high degree of stability for a given bullet and stability fails shown by sideways impacts - keep on looking and run everything over. Can't be positive it is a 1-10 until you check it out. If all else fails go for a shorter bullet but check things out using the JBM bullet length site and JBM stability calculator on line before spending $ on bullets.

I like H414 with 68-75 grain bullets in my .22-.250's. I once had a 1-10 twist .250 that shot the 68 Hornady bthp very well and that bullet is probably longer than the Sierra Tipped MK minus the plastic tip. The 69 Sierra Tipped MK is a real good long range varmint bullet and just as effective as many 6mms for that purpose.

Hornady call a 1;7 twist for the 68 bthp?

 

[Evlshnngns]

Sierra has a 60gr TMK at midway. Works with 10 twist or faster. It has roughly the same bc as the 69smk.

 

[284winner]

Hornady call a 1;7 twist for the 68 bthp?

No in a 22-250, the 10 should work for the 68 bthp. Buddy shoots those in a 9 twist 223. It may be a borderline 9/10 twist bullet but pushed at 22-250 speeds, the 10 should sounds it fine. Is your barrel a factory barrel, if so, who makes the gun ? May be that you are incorrect in twist rate. I once thought I had a 14 twist 22-250 barrel and turned out to be a 12. That's another option on why they aren't stabilizing.