Longrange PD cartridge - Part II

[Varmint Hunter]

Many of you have suggested that the 243 or 243AI with the 107gr SMK bullet would be the ideal longrange PD cartridge. My suggestion of the 22-243AI with a JLK 80gr did not seem to curry much support.

Here's my question:

Both the .224 80gr JLK and the .243 107gr Sierra bullets have very similar BC's, aprox .510 - .520. If the 22-243 can fire a high BC bullet @ 3,600 ft/sec and the 243(AI) can fire a bullet of similar BC @ aprox 3,000 ft/sec; how can the .234(AI) be a better longrange combination? The 22-243AI should shoot significantly flatter AND resist wind much better (similar BC and shorter flight time) than the 243(AI). The 22-243AI would also produce less recoil. As far as accuracy goes, I'm assuming that both cartridges are fired in quality rifles with the same potential for accuracy.

Am I missing something here?

VH

 

[jb1000br]

sierra says .420 for the 80gn and .527 for the 107.

also more weight=harder to move (80 v 107)
increased bore life
increased energy at longer range

those would be my reasons for the 243 ack.--also your gonna get more than 3000fps with a varmint length barrel in the 243 ack.

FWIW,
JB

 

[Darryl Cassel]

VH

The 6mm 107 gr MK has a .555 BC while the 105 JLK is higher then that.
The 80 gr barely breaks out of the .4 BC range and that is the difference in downrange flight.
Even "if" the 80 gr had a .500 BC it would not be a better choice then the 6mm for wind busting characteristics since it (6mm) has a .555 and higher BC rating.

Again, if the 80gr 224 bullet was so good, you would see it being used in 1000 yard matches, which you don't.
It's 6mm, 6.5 and 30 cals doing most of the winning with the 30s and 6.5 doing the best at some ranges and the 6mm and 30 cals at others.
I'm using the Williamsport and Montana ranges here for the cartridges/bullets used the most and also the records that have been broken.

I to have a 22/284 to make a good comparison and no way will the 80 gr 224 bullet do as well as the 105 or 107 gr 6mm bullet using the same length barrels and the same case size such as a 6/284 or the 243 case size.

The 80 gr bullet sheds it's velocity very quickly even though it starts out faster. This is because of the higher BC of the 107 and 105 gr 6mm Bullets.
Clearly a better choice for a longrange P-dog round out to 1000 yards or a bit further.

As the bullets diameter and weight increase the BC goes up in every instance as long as the bullets were designed as match type bullets to begin with. Even within the same diameter bullet, the higher weight is normally a higher BC if they are match bullets. A real good example of that is a 168 gr MK 30 cal compared to a 200 gr MK 30 cal.
A 224 BC is higher then a .17 Cal. a 6mm is higher then the .224, the 6.5 is higher then the 6mm, the 7mm is higher then the 6.5 and so on.
This is true in most every bullet made.

The true test of any bullet is actual fire and I have done it.
There will be less drop to get from point A to point B (1000 and 1100 yards) using the 6mm 105 and 107 gr bullets then my 80 gr 22/284 which does come out of the end of my barrel faster to start with then the 6mm.

For that original poster concerning this topic, lets look at throat erosion to. Running an 80 gr bullet in a smaller diameter barrel at 3500 to 3600FPS will create much more wear then the 243 or 6/284 will using a higher BC bullet and going a bit slower.

I like my barrels to last a bit longer.

Later
DC
As an add on here---The 6/284 is moving that 105 and 107 gr MUCH faster then 3000 FPS.
The 243 in a good 8 twist 30" long barrel is also.
Comparing energy levels--Hands down, goes in favor of the 105 or 107 gr 6mm bullets.

[ 11-06-2003: Message edited by: Darryl Cassel ]

 

[Varmint Hunter]

My Sierra manual lists the .243, 107gr MK @ a BC of .526. The JLK 80gr .224 was listed at .510. That is a fairly small difference in BC, especially when the launch speed of the .224 bullet is 500+ ft/sec faster.

Yes, the Sierra 80gr has a relatively low BC, which is why I do not prefer it when varminting at long range.

Another question:

If a .224 bullet and a .243 bullet had the same BC and were fired at the same MV, wouldn't they both have the same bullet drop and wind resistance?

I am not in disagreement with the results that you have seen on paper, but am having a hard time in understanding why this would be. I think I'll take another look at the ballistic calculator.

VH

 

[Varmint Hunter]

Just got done with the ballistic calculator and here is what I got when comparing the two. I also increased the speed of the 107 Sierra to 3,100 ft/sec.

Both were calculated with a 100yd zero.

22-243AI 80gr @ 3,600 drop @ 1,000yd -189.3"
10mph wind + 61.4"

243AI 107gr @ 3,100 drop @ 1,000yd - 263.5"
10mph wind +73.4"

It sure seems like the 22-243AI has the 243AI beat in this comparison. Opinions

VH

[ 11-06-2003: Message edited by: Varmint Hunter ]

 

[TH]

VH,
My cousin and I have expermented with the 22/284 we were having problems with the 80 JLK and the 80 SMK at 3500-3800fps+ they were exploding 20 yards right out the barrel. We also shot this gun at several 1000 yard matches our best groop was a 9 inch 5 shot groop at the Ohio club. If there was any wind at all the bullet would blow two targets down. we had a very hard time competing and even keeping it on paper.
Also at the high velocity we only shot 500 rounds through the barrel before it was shot out. Needless to say we rebarreled it to a 6.5/284 and have been very successful.

 

[Varmint Hunter]

I didn't think it was possible to disintegrate a Sierra 80gr SMK with its heavy jacket. There must have been something awful going on in that barrel.

Many shooters have experienced this problem with the 75gr A-Max bullet and fast twist barrels, but the Sierra and JLK bullets normally hold up pretty well.

My favorite long range varmint load shoots the 75gr A-Max @ 3,668 ft/sec. I have never had a single bullet fail to get to its target intact. I attribute this to a smooooth Hart barrel, moly coated bullets and ammo that is loaded about .006" into the rifling. The 75gr A-Max is a devastating bullet on Pa groundhogs.

It is interesting to hear that you guys have had problems with these bullets in the wind. The ballistic programs would indicate otherwise. I have never had the opportunity to shoot this cartridge @ 1,000 yds (except in the field) so will rely on your input.

For the record, I also shoot varmints with a custom rig in 6mmAI but have really become fond of the 22-243AI. It has produced many of my longest kills.

VH

 

[chris matthews]

VH,
All the other guys are right on the money. Not saying you're caliber is bad but in this situation the 243 is better.
Call Kevin Thomas at Sierra and ask him about the computer data. He'll tell you that beyond 300 it's pretty much an educated guess. Real world is not accurately portrayed in the ballistics programs. The wind does not blow at 9 oclock position at 10 mph from muzzle to the 1000 target. The guys on this site shoot and shoot often, me included, at 1,000 or beyond. They have real world experience. Now that's not saying you can't do it with the 22-243 you can as a 1000 record was held for awhile by a 220 Swift and I have seen a 6" 1000 yrd group shot by a 17 Rem.
Fact is the 243 will be more consistant than the Cheetah(basically what you have), 17, Swift etc. But the 300 WSM, RUM or 338 Lapua will outperform the 243.

 

[Darryl Cassel]

VH

As per the Oehler Ballistics program which I feel is one of the best and closest to actual BCs.

Sierra MK 107 Gr 6mm----.555BC

Sierra 80 Gr MK 224 bullet---.420


These BCs fall in line with what I have found to be true in actual fire situations using both bullets in my 22/284, 6/284 and my 243 with a 30" barrels and 8 twists.

I to am fond of my 22/284 but the fact remains, the 6/284 and the 243 at extended range is much more consistant and produces less throat eroasion then the 224 bullet does at high velocity, especially 3500, to 3600 Fps.
Many high velocity 22s are shot out in 600 rounds or less. I know of one that was gone at 400 rounds.

As mentioned, if the 80 gr 224 was so good, it would be used and winning 1000 yard matches consistanly but, it don't.
That's why I agreed with another poster that the 243 would be a good choice for his P-Dog shooting out to 1000 yards, plus a bit.

If I'm going to shoot 500 rounds per day (or more) at 800 to 1000 yards, I'll take the 243 with a 30" barrel and 8 twist shooting the 105 or 107 gr bullets.

Later
DC

 

[DMCI]

Gentlemen:

I have a .260 that I have used for several years with the 100 grain Sierra Varmint at about 3270 fps. This is a dandy round when a little wind comes up in South Dakota (Try 18mph for a start.) My experience tells me that this combination runs out of gas at about 700 yards.

I am further experimenting with the 7mm WSM.

That thing will put out a Burger 180 VLD (BC=.698) at about 2850 fps. My ballistics calculator tells me that I can get to 1000 yards with a come up of about 25 moa. (Sierra is about to launch a 175 SMK for this caliber as well.)

The rifle will also extrude a 100gr Sierra Varmint HP at a little over 3500, but I'm told a steady diet of these is not advisable. I will probably take 20 or so to the next hunt in case things need to be livened up a little.

[ 11-06-2003: Message edited by: DMCI ]

 

[MAX]

Perhaps of small import to this discusson, but I'd think the .22 will require a faster twist and this compounds Yaw of Repose issues. Between that and short barrel life for the CHeetah I'd go with the .243 and never look back. Truth is I'd probably opt for a 6.5 or larger still. LONG range requires precision and it's easier to find with larger bores. Faster ain't always bester. You asked for advice and got some good stuff from Darryl.

Of course if you just really want a hotshot .22 I'd understand that without jumping thru all the rationalization part. There is always the Barnes QT approach if you want to make your own 125 gr. .224 bullets and use a 5" twist. I'm sure the BC is high, even if the velocity is mild...

Mebbe with a Rigby case though....

Best of luck with your choice. I've felt your pain.

 

[jb1000br]

it would be a great PD gun--but the barrel may only last one day on the town if you arent careful--definately want to pick your shots with that one.
i'l stick withthe 223 for high volume PD shooting--and 243ack and above for long PD's

JMHO,
JB

 

[blaster]

The 243 AI will push a 107 gr much farter than 3100 f/s I know they will go to 3400 f/s. My 6 BR is running 107's at 2900f/s. Also look at the 105 Berger bc .562 or the 95 berger bc .524 and can be pushed faster than the 105's. The 1000 yds BR shooter like to run the big bullets at 3100 to 3150 f/s for better accuracy but your 243AI & 6mm AI will run them much faster. but the 22-243 would make a good PD gun.

 

[lynn]

To answer Varmint Hunters questions yes two bullets with the same bc fired at the same speed reach the target at the same time(same flight time),have the same amount of drop and or affected by the wind the same amount.The only difference is the retained energy at the target.The 22/243 isn't as inherently accurate as a 6br and small things such as fouling disrupt the smaller bullet to a larger degree.Due to the high bc of some bullets the 22 was tried at 1000 yards but bc alone doesn't mean anything without accuracy and that is why they aren't used .Remember Lost River sells .930 bc 30 cal 220 gr J40 bullets which are much better BC wise than anything mentioned even 300 gr Sierra 338 cal but nobody shoots them because they simply don't shoot accurately enough for a competition rig.Another case would be Sierras 155 gr 6.5mm with its higher bc number than the 142's if it aint accurate forget it.
I have a 6/284 that shoots the 107's to a little over 3400 fps but best accuracy is at 3200 fps so it sits in the closet.My 6-06 shoots the 107's very accurately at 3433 fps with 57 grains of H1000 a Fed 210M primer and Lapua 30-06 brass necked down so it gets used all the time.When the barrels wear out the tide may change and the 6/284 may shoot better at the upper velocity range and therefore get used more often.The Sierra Match bullets tend to be easier to keep tuned and easier to tune initially in my opinion so they get the nod when it comes to extended sessions of Prairie Doggin.Run a ballistic program on the 6mm 107 at 3433 fps coupled with great accuracy and you have a winning combination.
Lynn