lehigh 185

[Deleted]

Does anyone know why Lehigh's .40 185gr DOA measures .403, well with a crush of the calipers it measures .4025? Hornady SST's and Barnes are running right at .400 and .399 compressed. Might not sound like much but it is in tight bored guns. I received a sample pack from Lehigh, and two other batches from individual sellers and they all measure the same.

[lakeplainshunter]

Are you measuring over the knurls? They are a few thousandths bigger when you do.

[Deleted]

Yep over the knurls. The knurls are part of the bullets diameter IMO.

[grouse]

Feb 1, 2011 13:11:55 GMT -5 @45omega said:

Yep over the knurls. The knurls are part of the bullets diameter IMO.

True, the reason why is so the knurls grip the sabot and then prevents or helps the bullet from slipping inside the sabot.

[sabotloader]

45omega

The knurls compress into the sabot and should not add any significant loading pressure. These knurls prevent the sabot from slipping on the outside of the bullet. If the slip occurs - the bullet will not reach the optimum revolutions per minute.

[Deleted]

They do load tighter then SST's and Barnes. I can use a Harvester crushed rib to help loading. I was just curious as to why they were bigger than .400 and my question was answered.

[jsthntn247]

Can't tell you much about the diameter of them, but they do a nice job on whitetails. I shot two does (dmap program) the last day of the season. Both ran 40 yards and fell ten feet from each other. They had 1/2 fist sized entrance holes with diameter sized exits just as advertised.

[dave d.]

:)I have a question how does one know if a bullet slips or rotates in a sabot? Thanks

[Deleted]

Feb 11, 2011 6:58:00 GMT -5 dave d. said:

:)I have a question how does one know if a bullet slips or rotates in a sabot? Thanks

That's a good question. Once I start the bullet I cannot see what it does. Seating the bullet on the powder charge should push the bullet to the base of the sabot if a "slip" had occurred. Heck I do not even know if the Spinjag is actually spinning the bullet as they claim.

[deadon]

Feb 11, 2011 7:39:14 GMT -5 @45omega said:

Feb 11, 2011 6:58:00 GMT -5 dave d. said:

:)I have a question how does one know if a bullet slips or rotates in a sabot? Thanks

That's a good question. Once I start the bullet I cannot see what it does. Seating the bullet on the powder charge should push the bullet to the base of the sabot if a "slip" had occurred. Heck I do not even know if the Spinjag is actually spinning the bullet as they claim.

I know that if I only tighten my spinjag finger tight, It unscrews each time I load a bullet so it is not spining then. If I tighted it with a small wrench it does not unscrew. Is it spinning, who knows Rusty

[sabotloader]

dave d.

Maybe I missing the point of your question Dave, but I will throw this out there... I do not think you were asking about bullet slip in the sabot while loading. I think you might have been more concerned about slippage on the way out. When I mentioned it that is what I was referring to.

First a micro bit of history.... On occasion people had wondered about the slippage of regular smoothed walled pistol bullets while in the sabot after the charge is ignited and violently pushed up the bore.

Here is a picture of the new .458/300 grain Lehigh showing it in a MMP Orange sabot and another bullet on the side that you can see the knurls (barbs).



When the assembly is inserted into the bore (with or without a QLA) the sabot sqeezes down on the the bullet, the barbs then insert themsleves into the ploymere. As you push the load down the bore with a loging jag - either a spin jag type or even a fixed jag - bullet is forced to the bottom of the sabot and the entire assembly turns its way down the bore. PROVIDED, that you have the proper fit of sabot to bore. With a jag that spins the and if the friction is great enough the jag spins its way way down the bore with the bullet remain in place and stationary in the jag cup. With a fixed jag the same action occurs but either the bullet will slip in the jag - copper or brass even lead on the brass loading jag will spin internally in the jag or as suggested the jag will unscrew itself if it is not installed tight.

But none of this is the main prupose of the barbs (knurls). It all goes back to the old law... a body at rest tends remain at rest... other wise a body not spinning does not want really spin when pushed forward.

A lot of folks spend a lot of time trying to get bore oils out of the bore prior to shooting a projectile. The procedure is usually done to insure that the sabot or sabotless bullet 'grips' the bore and as it rapidly pushed forward the projectile starts to spin right away with any slippage over the lands.

The barbs on the Lehigh are ment to lock the projectile to the walls of the sabot so that when the sabot starts its spin, even a violent start to the spin, the bullet spins at the same rate as the sabot. Stabilization of a bullet is detirmined by RPM of the bullet not the sabot as the sabot leaves early. If both the sabot and the bullet are spinning at the same rate and the rate established by the lands and grooves in the bore - accuracy should be there at the end of the bullet's flight path.

Lehigh is also workin on the developement of a sabotless bullet also. You can see on the sabotless, it has simular barbs to grip the lands and grooves, they also act as a partial gas seal.



Hope this explains what I think I am explaining... The other point I should add these are my thoughts Lehigh Dave might have a somewhat different answer.

[dave d.]

:)sb thank-you for the detailed post. I remember a post back know from awhile back about slipping and the bottom line was if a bullet slipped upon ignition the bullet would drill the bottom of the sabot.did you ever shoot them unknurled? If so did they drill the sabot?

[sabotloader]

Feb 12, 2011 15:42:45 GMT -5 dave d. said:

:)sb thank-you for the detailed post. I remember a post back know from awhile back about slipping and the bottom line was if a bullet slipped upon ignition the bullet would drill the bottom of the sabot.did you ever shoot them unknurled? If so did they drill the sabot?

No, I have not shot a Lehigh that did not have the Knurling? Oh, that is not true I have shot a Lehigh without Knurling... I forgot Lehigh makes a .458/300 grain bullet for 45-70's (I call it their buffalo bullet). I have shot quite a few of these and they shoot very well.



In fact they shot so well I doubt that they did slip in the sabot and they did not drill the bottom of the sabot as far as I know. also I have shot a lot of other bullets and I can not say that I have ever witnessed a drilled sabot.

[lehigh]

Projectile/sabot slippage is a significant design consideration. Bullet rpm = muzzle velocity x 720/ twist rate. A .45 caliber projectile will be revolving at around 60,000 rpm. The transfer of rotational energy is dependent upon an approximate 10 grain sabot transferring rotational energy to a projectile weighing twenty times greater in less than one millisecond. Projectiles are usually designed to achieve a stability factor of at least 1.5. For brass bullets, having a lower density than jacketed bullets, stability is extremely critical. We have found, depending on muzzle velocity, barrel twist, and projectile weight, it is common to lose four to six inches of twist on a saboted bullet. This loss can be through rotational energy transfer from the barrel to sabot and/or from the sabot to bullet. As Lehigh bullets are long for caliber to achieve a high ballistic coefficient, we knurl the bullet to mitigate this rotational energy loss. I hope this helps. Thanks, Dave

[dave d.]

:)thanks sb and dave.