300 Win Mag Woe

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Bluffton Bill

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A while back I picked up a box of Barnes 165 grain triple shocks and stuffed them overtop about 77 grains of IMR 7828. The resulting group at 100 was 3/4 of an inch! I thought wow! So I loaded up 50 rounds. I cleaned the heck out of the gun with a copper solvent, dry patched it out, and them ran a little hoppes through it. A few weeks later I took the 300 out to check it and after a couple of fouling shots I let her cool down and them tried for a group. No dice. The best I could get was about 2 ". After examining all of the ammo I noticed that the COL was varying slightly between rounds. I thought that maybe since it was a compressed load the bullets were pushing back out, but since I didn't have any trouble with the first 8 I had loaded I dismissed this. I ran everything back through an RCBS seating die to what I figured was 3.32 (Max is 3.34 but won't clear the mag.). Something still wasn't right as you could see from the grooves on the triple shocks that not every round was the same. Then it dawned on me that maybe the ogive on the bullets was not consistant. Anyone have a different thought??? When I set my die up I put the case in (unloaded), screw the die down until it contacts the top of the case and then back it up a crack. I back off the set screw on the top of the die and then partially seat the bullet. I continue to seat and readjust until I have the desired COL is obtained. Then I load my charged cases. Am I doing something wrong. I havn't had problems with HDY or Nos. bullets, but I'm a rookie reloader.:confused:
 
If the powder is pushing the bullet out, I'd try to crimp each bullet in place. I've had the best luck crimping when doing it as a separate operation from seating. If you can set up a second press that speeds the operation. Begin by raising or removing the seating stem from the die. Run the ram to the top of it's travel with a round in the shell holder, then screw in the seating die until you feel contact with the case. Retract the ram, turn the seating die in about an eighth of a turn, then push the ram to the top of the travel and you have a properly crimped round. Be careful - if you lower the die too far you will squash the case - make all adjustments in small incriments. Adjust the height of the die for each cartridge, and this will make up for differences in over all length. Retract the cartridge from the crimping die, give it a half a turn, then run it into the die again to ensure that the crimp is uniform. Crimping the rounds will prevent the bullet push out, but it will also produce a uniform bullet pull weight.

I doubt if there is going to be a difference in bullet ogive length, but you can check it by placing the bullet nose down in the muzzle of the rifle, then turn the base of the bullet, and a scored line will appear on the bullet. This can then be measured from the base of the bullet with a micrometer.

Slight differences in over all length will not create accuracy errors which are detectable with hunting rifles. If you are judging by the marks on the bullet, you might be just seeing variances in your case length.

By the way - when you set up your seating die, it seems to me you did things correctly. Here's what I think. I think there was something different between the first day you shot and the second. Gusts of wind, shooting from a hard surface, poor light, anxious to shoot and not paying attention to proper form etc.
 
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Thanks for the reply Boomer

Thanks,

I may try crimping. Once I noticed the marks on the bullets were lining up differently with the case I ran everything through my micrometer and it varied from 3.30 to 3.34. Confusing because once I had my die set it didn't move at all. All the cases were brand new out of the bag and I checked them before loading them, all were the same length (As an aside, should I be full length resizing brand new cases?). As for different conditions. Right after I put the 300 back in the rack, I sat down with my 7 Rem Mag and put 3 175 HDY's into one ragged hole. The anxious part may have something to do with it as I have to be in the right mood for the 300's recoil. Your likely right that the main variable may have been me. Maybe I flinched!
 
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how many groups did you fire when you got the 3/4" group? If only one then it may just be that conditions of wind, humidity, shooter state of mind were at the right level that day, and these conditions have since changed. When developing loads I find I need to do tests at least 3 or 4 times (doing say 4 different powder loads at a session) and pick the load which gives better groups each time.

As suggested above, crimping will produce consistency as well,
 
I have had similar problems with TSX bullets, they can be very sensitive to seating depth. Mine like 75.5 gr of reloder 22 with the same bullet, no compression.
 
Martinbns,

I was wondering about the seating depth thing. I followed the Barnes manual instructions to the T, but the resulting cartridge will not fit into the magazine of a M70 300 win. mag. (at least not into mine) . They are simply too long. I am seating to about 3.32 to ensure good clearance. This puts the bullet several thou. off the lands? I wonder if the TSX is just too long a bullet for this cartridge (or will take too much fiddling to get results-I'm a bit of a minimalist).
 
Have you gauged your throat length with a Stoney Point? I'm thinking that 3.320 is way, way too short an OAL for these bullets in a .300 Winchester Magnum. Most rifles in this chambering have magazine boxes that will accommodate a cartridge loaded to 3.500, so they have lots of room to work with and can seat the bullet .030 off the lands, which is generally the best in terms of accuracy for the TripleShocks. If I recall, I'm seating the 168 TripleShock a little over 3.420 in my rifle, and it still has a fair amount of jump.

Also, I'd try a faster powder than 7828 with these bullets. If you like IMR powders, I'd try IMR 4831. H4831 is a good bet, too (it's what I use). Others have done well with Reloder 19 and 22. I'm sure Vihtavuori N160 or 560 would also be excellent.

In truth, if I had a magazine box limitiation like yours, I'd stay away from the TripleShock or any of the newer VLD type of hunting bullets. Instead, I'd try either the Speer Grand Slam or MagTip, or the Nosler Partition Protected Point (NOT the regular Partition, which has a very long lead point). These bullets have slightly flattened noses, which means you can get closer to the rifling without exceeding 3.340. They have excellent reputations for accuracy, as a result (as do roundnosed bullets, for the same reason). My brother-in-law has a Browning BAR in .300 Winchester Magnum which has a small magazine box like yours. He wants me to load for him, and I've told him that he needs to pick up one of these bullets and should not even think about the longer designs like the TripleShock or the Nosler Accubond unless he is satisfied with erratic performance.

Best of luck.
 
Bluffton Bill said:
Martinbns,

I was wondering about the seating depth thing. I followed the Barnes manual instructions to the T, but the resulting cartridge will not fit into the magazine of a M70 300 win. mag. (at least not into mine) . They are simply too long. I am seating to about 3.32 to ensure good clearance. This puts the bullet several thou. off the lands? I wonder if the TSX is just too long a bullet for this cartridge (or will take too much fiddling to get results-I'm a bit of a minimalist).
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I'm lucky, mine is a Sako AV with a 3.6 inch magazine and my overall length is 3.544, just .020 off the lands. I have found with a variety of rifles with only a couple of exceptions, If I cant get within .050 of the lands barnes bullets aren't very accurate. I've never shot them, but a buddy who has the same rifle as you uses Nosler partition protected points so he can load them kissing the lands, most recent bullet designs will be too long and pointy(technical term) for your rifle.
 
Thankyou for all the help. Looks like I'm pulling bullets tonight! The TSX's are going to be used up in my Ruger 30-06. I'll be able to seat them properly with this rifle.
 
Bluffton Bill said:
Martinbns,

I was wondering about the seating depth thing. I followed the Barnes manual instructions to the T, but the resulting cartridge will not fit into the magazine of a M70 300 win. mag. (at least not into mine) . They are simply too long. I am seating to about 3.32 to ensure good clearance. This puts the bullet several thou. off the lands? I wonder if the TSX is just too long a bullet for this cartridge (or will take too much fiddling to get results-I'm a bit of a minimalist).
Click to expand...

remove the spacer from the rear of your mag box. This will allow OAL's to about 3.6".....the way the rifle should have been built in the first place.
 
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