RELOADING 243 AND GETTING LOW SD AND ES

[wbm]

the 85 grain Sierra BTHP, the latter an all purpose bullet for the 243 meaning capable of varmints / predators and with proper shot placement, deer

Years of experience with this bullet. Outstanding performance on deer.

 

[Savageseven]

Lapua brass is very good, but not necessarily perfect. The fact that it is virgin brass might play a role, but I have gotten decent ES/SD values out of prepped virgin Lapua brass many times, so it's hard to say. Turning the necks might make a difference. Also, if you're sizing the necks down to a slightly smaller diameter and following that up with a mandrel that is .002" under bullet diameter, you're probably running about .0025" neck tension due to spring-back of the brass. It might be worth testing mandrels that are ~.001" and/or ~.0015" under bullet diameter, if you have them. Finally, trying a different primer can sometimes make a world of difference. Sometimes experimenting with individual steps in the brass prep/reloading process, isolating each step and making some change at only that step is the only way to pin down the culprit(s). Again, best of luck with it.

im using Federal Gold Match large rifle . GM210M If i switched to the Federal Gold 215M Magnum primers would this be a better choice you think or would it make things worse as far as lowering my SD

 

[Ned Ludd]

im using Federal Gold Match large rifle . GM210M If i switched to the Federal Gold 215M Magnum primers would this be a better choice you think or would it make things worse as far as lowering my SD

Hard to say, I've never used the 215s, only 210s. As you noted, the 215 is a magnum primer. But it might not hurt to try. If you decide to try them, you might back off on the charge weight by a couple or three tenths grain charge weight until you know what the 215s will do to your velocity/pressure, as compared with the 210s. I have compared CCI and Russiam small rifle magnum primers in the past with Fed 205s and they seemed to increase velocity by about 25-30 fps in a .223 Rem load. In those particular cases, I did not observed a noticeable improvement in ES/SD, but the loads I tested had initially been worked up with Fed 205s and were already giving acceptable ES/SD values, so there wasn't really all that much room for improvement anyhow. Backing off on the load a bit if you try the magnum primers is merely a safety precaution.

 

[Capt. Oblivious]

I might have missed it but what did the groups look like?

 

[Savageseven]

Hard to say, I've never used the 215s, only 210s. As you noted, the 215 is a magnum primer. But it might not hurt to try. If you decide to try them, you might back off on the charge weight by a couple or three tenths grain charge weight until you know what the 215s will do to your velocity/pressure, as compared with the 210s. I have compared CCI and Russiam small rifle magnum primers in the past with Fed 205s and they seemed to increase velocity by about 25-30 fps in a .223 Rem load. In those particular cases, I did not observed a noticeable improvement in ES/SD, but the loads I tested had initially been worked up with Fed 205s and were already giving acceptable ES/SD values, so there wasn't really all that much room for improvement anyhow. Backing off on the load a bit if you try the magnum primers is merely a safety precaution.

ok sounds great. just curious when im working up a load i use the nosler load book and use the suggested powder they recommend. i start with their starting load and make 4 round strings in each weight then jump to the next by .5 grain increments. is this to much ? would i miss a good load ?

 

[Mulligan]

Maybe this has been covered above and I missed it? If so, my apologies

I had a similar experiance using Lapua brass. Fact is, the necks were a bit thicker then expected and I didn’t measure the loaded round after buying some Lapua brass. The problem ended up being the variation in clearance in the neck of the chamber. This was on 7-08, it shot just fine with Remington brass, and had what you would expect for velocity and extreme spread. I carefully worked up a load with the same components using Lapua brass and accuracy was not pretty. It really was just me making a rookie mistake and assuming everything should be good in normal (not tight neck) chamber.
I turned the necks a little and my world was round again.
Just something to ponder.
CW

 

[Savageseven]

Maybe this has been covered above and I missed it? If so, my apologies

I had a similar experiance using Lapua brass. Fact is, the necks were a bit thicker then expected and I didn’t measure the loaded round after buying some Lapua brass. The problem ended up being the variation in clearance in the neck of the chamber. This was on 7-08, it shot just fine with Remington brass, and had what you would expect for velocity and extreme spread. I carefully worked up a load with the same components using Lapua brass and accuracy was not pretty. It really was just me making a rookie mistake and assuming everything should be good in normal (not tight neck) chamber.
I turned the necks a little and my world was round again.
Just something to ponder.
CW

what should one expect for velocity in a 243 with 26 inch heavy varmint barrel ? using 4064 powder or imr 4350

 

[Savageseven]

I might have missed it but what did the groups look like?

goups at 100 yards were about the size of a quarter

 

[Mulligan]

what should one expect for velocity in a 243 with 26 inch heavy varmint barrel ? using 4064 powder or imr 4350

The point I was trying to make is if you do not have enough clearance between the loaded round and the neck of the chamber you can get pressure spikes causing significant increases in velocity. This in turn will cause your extreme spread to be rather large.
CW

 

[Savageseven]

The point I was trying to make is if you do not have enough clearance between the loaded round and the neck of the chamber you can get pressure spikes causing significant increases in velocity. This in turn will cause your extreme spread to be rather large.
CW

yep i undedrstand that. i have a ball mic and i will check wall thickness on the lapua brass as well as the OD on a loaded round. But was wondering what a guy should shoot for as far as a velocity in the 243 with 70 grain nosler ballistic tips

 

[Mulligan]

yep i undedrstand that. i have a ball mic and i will check wall thickness on the lapua brass as well as the OD on a loaded round. But was wondering what a guy should shoot for as far as a velocity in the 243 with 70 grain nosler ballistic tips

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Looks like they can be kinda zippy

CW