150 gr. Hornady SST

Devildog101 · October 19, 2016, 10:23 PM

I was preparing my seating die to seat 150 gr. SST to 2.220 oal. This was going to be well below the canalure. Has anyone else loaded this particular bullet? Is so, did you press down to the canalure or stop at 2.220? I'm worried about bullet jump to throat.

**Unclenick** · October 20, 2016, 08:51 AM

Welcome to the forum.

Jump doesn't always spoil accuracy. Sometimes it helps. The dynamics of the bullet and gas and the chamber geometry are complicated. Unfortunately you just have to test to see what your gun likes.

As far as seating the cannelure out, that's only a problem if you are chambering the round violently, as having less bullet in the neck makes it easier to tip it off-axis. I would not seat it too shallowly if I were shooting the ammunition in a semi-automatic action of any kind. If you are single-loading a manual action you can do pretty much whatever you want. Just keep in mind that the closer the bullet is to the lands the time initial gases have to bypass it before it obturates the bore. With less gas bypass, peak pressure increases. (see below). So if you want to load with a bullet very close to the lands you want to work the load up that way so as not to get excess pressure. A minimum load with contact can make as much pressure as maximum load does without contact.

Dufus · October 20, 2016, 10:33 AM

I always give some room in the chamber to allow for variances in bullets. This is known as manufacturing tolerances. Some can vary as much as 0.005" or a tad more.

If you are not prepared, jamming bullets into the lands can be exciting to say the least.

Just to note: the most accurate load I have ever developed had a 0.205" jump to the lands. I still load it. I have also learned that hunting ammo does not need to be seated close to the lands.

T. O'Heir · October 20, 2016, 12:05 PM

You can forget the cannelure altogether.
Hornady makes 3 150 grain SST's. Two of 'em are .30 cal., the other is a .277. No 2.220" OAL for any of 'em. Which cartridge you using?
The Max OAL depends on what cartridge you're using, not the chamber dimensions.
The off-the-lands stuff can wait until you have a load. It's a load tweaking technique you can forget about too if you want. It's not critical. It's different for every single rifle anyway and is found by trial and error. There is no absolute number for how far off for any cartridge or rifle.

CarJunkieLS1 · October 20, 2016, 12:45 PM

I'm going on a limb and guess you're loading 300blk with the 150 SST. If its below the cannelure and shoots and feeds well then don't worry about it. The cannelure is most likely placed for a COAL for the .308 or 30-06.

cdoc42 · October 23, 2016, 12:38 AM

Devildog,I don't think you can use the position of the cannelure to determine seating depth. You need to determine how far the ogive of the bullet is from the beginning of the rifling (the "leade") and that depends on the rifle.

For example, my 300 WSM allows a 150gr SST to be seated that it fits in the magazine such that the distance from the mouth of the case to the TOP of the cannelure measures 0.064." Nothing below the cannelure shows. That happens to be 0.02" from the rifling(lucky) and the overall length, ogive to base of the case (OAL-OG)is 2.241."

In my .270 Remington 700, a 140gr SST at 0.02" from the rifling shows a measurement, from the mouth of the case to the top of the rifling to be 0.233." A LOT of the area below the cannelure shows. The OAL-OG is 2.837."

I provided the OAL-OG measurements because you didn't tell share what caliber you have. The differences I have are caliber specific for my rifles.

firewrench044 · October 23, 2016, 08:14 PM

I use 150gr Hornadys in 308 and 3006
Its a very good bullet
In 308 I seat them at 2.800 COAL, the cannalure is fully exposed
( its magazine length in 6 rifles )( I do not crimp them )
( but as a hunting bullet I do seal them )

I have taken deer at 50 yards and 450 yards with them

I am curious, does the new SST bullet have the new tip that does
not melt from air friction ? ( they had a problem with that )

October 19, 2016, 10:23 PM	#1
Devildog101 Junior Member Join Date: October 19, 2016 Posts: 1	150 gr. Hornady SST I was preparing my seating die to seat 150 gr. SST to 2.220 oal. This was going to be well below the canalure. Has anyone else loaded this particular bullet? Is so, did you press down to the canalure or stop at 2.220? I'm worried about bullet jump to throat.

October 20, 2016, 08:51 AM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	Welcome to the forum. Jump doesn't always spoil accuracy. Sometimes it helps. The dynamics of the bullet and gas and the chamber geometry are complicated. Unfortunately you just have to test to see what your gun likes. As far as seating the cannelure out, that's only a problem if you are chambering the round violently, as having less bullet in the neck makes it easier to tip it off-axis. I would not seat it too shallowly if I were shooting the ammunition in a semi-automatic action of any kind. If you are single-loading a manual action you can do pretty much whatever you want. Just keep in mind that the closer the bullet is to the lands the time initial gases have to bypass it before it obturates the bore. With less gas bypass, peak pressure increases. (see below). So if you want to load with a bullet very close to the lands you want to work the load up that way so as not to get excess pressure. A minimum load with contact can make as much pressure as maximum load does without contact. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

October 20, 2016, 12:05 PM	#4
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	You can forget the cannelure altogether. Hornady makes 3 150 grain SST's. Two of 'em are .30 cal., the other is a .277. No 2.220" OAL for any of 'em. Which cartridge you using? The Max OAL depends on what cartridge you're using, not the chamber dimensions. The off-the-lands stuff can wait until you have a load. It's a load tweaking technique you can forget about too if you want. It's not critical. It's different for every single rifle anyway and is found by trial and error. There is no absolute number for how far off for any cartridge or rifle. __________________ Spelling and grammar count!

October 20, 2016, 10:33 AM	#3
Dufus Senior Member Join Date: December 10, 2014 Posts: 1,965	I always give some room in the chamber to allow for variances in bullets. This is known as manufacturing tolerances. Some can vary as much as 0.005" or a tad more. If you are not prepared, jamming bullets into the lands can be exciting to say the least. Just to note: the most accurate load I have ever developed had a 0.205" jump to the lands. I still load it. I have also learned that hunting ammo does not need to be seated close to the lands.

October 20, 2016, 12:45 PM	#5
CarJunkieLS1 Senior Member Join Date: October 1, 2013 Posts: 686	I'm going on a limb and guess you're loading 300blk with the 150 SST. If its below the cannelure and shoots and feeds well then don't worry about it. The cannelure is most likely placed for a COAL for the .308 or 30-06.

October 23, 2016, 12:38 AM	#6
cdoc42 Senior Member Join Date: March 13, 2005 Location: Pennsylvania Posts: 1,687	Devildog,I don't think you can use the position of the cannelure to determine seating depth. You need to determine how far the ogive of the bullet is from the beginning of the rifling (the "leade") and that depends on the rifle. For example, my 300 WSM allows a 150gr SST to be seated that it fits in the magazine such that the distance from the mouth of the case to the TOP of the cannelure measures 0.064." Nothing below the cannelure shows. That happens to be 0.02" from the rifling(lucky) and the overall length, ogive to base of the case (OAL-OG)is 2.241." In my .270 Remington 700, a 140gr SST at 0.02" from the rifling shows a measurement, from the mouth of the case to the top of the rifling to be 0.233." A LOT of the area below the cannelure shows. The OAL-OG is 2.837." I provided the OAL-OG measurements because you didn't tell share what caliber you have. The differences I have are caliber specific for my rifles.

October 23, 2016, 08:14 PM	#7
firewrench044 Senior Member Join Date: July 9, 2007 Location: Fort Pierce, Florida Posts: 381	I use 150gr Hornadys in 308 and 3006 Its a very good bullet In 308 I seat them at 2.800 COAL, the cannalure is fully exposed ( its magazine length in 6 rifles )( I do not crimp them ) ( but as a hunting bullet I do seal them ) I have taken deer at 50 yards and 450 yards with them I am curious, does the new SST bullet have the new tip that does not melt from air friction ? ( they had a problem with that )