ihmsa forums

would 120gr bullet @2100fps giving 816 ft/lbs @rams be enough energy to take them down? 129gr gives 832 ft/lbs @ 2000fps

I have no idea if this is accurate or not, but I have heard it said many times that a momentum factor of .9 is required to reliably take rams under most all environmental conditions.

Steve W.

Not sure which cartridge you are refering to or just making a general statement. I presently shoot a 6.5TCU in a 10" contender using 120gr bullets at around 1850 fps and do not have problems with properly set rams. There are some momentum calculations out there somewhere to calculate the necessarey momentum for rams. I do not know it off the top of my head but if you just search for something like IHMSA ram momentum calculation you are sure to find something.

Bret

that is for a 6.5tcu and i found the formula for striking momentum

correct if they do not fall they do not count, so what is enough for an improperly set ram,how much will always be enough

It is easy enough to calculate a momentum value. Multiply 225200 by .95, then .9, then .85 etc until you create a chart. An easy example is a 168gr bullet striking the ram (or any) target at 1000fps. Velocity x weight = 168000 which is close enough to 168900, the momentum value of .75 lb/sec. As you can tell, heavier bullets dont need to impact at speeds required of lighter bullets. In a second example, a 100gr bullet must impact at 1689 fps to equal the same value.
Now that you can calculate impact velocity you need to determine if your cartridge will create enough muzzle velocity so you still have enough terminal velocity. www.jbmballistics.com can be of use here.
Momentum favors weight. Also you must decide if you want a .30cal 240gr bullet or a .44cal 240gr. While they may both apply the same momentum to a target, they certainly wont fly the same. Neither will a 7mm 100gr and a 44cal 100gr. Have fun. rp

I used a 120 in a 25x39 going 2100 fps that very rarely failed to take a ram. In a 6.5 with a shorter bullet you could have some problems. Less dwell time pushing on the target.

I've used 95gr bullets in my .243 and take Rams reliably. They are traveling a little faster though... 2400-2700fps (I'm too lazy to chrono). Depending on the manual, that's what I'm getting...


Chris

no load will always be enough. your load should be o.k. 99.9% of the time to take down rams. i switched over to 150 gr bullets in all my 7mm guns after ringing several with 140 gr and have never left a ram standing with them. the velocity ranges from 1800 fps to 2000 fps in several of my silhouette guns. allen

I like Allen have used 139/140 and 150/154 grain bullets in a 7br for years. I can't recall ringing a ram with any of them. I'm sure I have, just can't recall one. We have a shooter at home that has problems with one particular ram. He uses a 6.5br and a 129? bullet. Have no clue why he sometimes rings it. I have gone before and after him and knocked it down with a .357 magnum with my field pistol load and a .223 with a 60 grain bullet. As Allen said no normal load is 100%. I'm sure everything we use has rang a properly set ram at least once. In 1987 I saw a properly set pig rung with a unlimited gun in 7mm at the Internationals.