243 cast load help

[newton]

Got my hands full this month working on my sons 308 and my nephews 243. I started out just getting both rounds read, prepping cases and making boolits. Then when the rain finally let off I decided to mess with the 243 first.

I am loading the RCBS 95 grain boolit. Using IMR4227. I started out with 5 rounds each of 13-18 grains. I did load the 17 and 18 grain charges with three different lengths mainly on the hunch that the 1950fps mark is where I need to be(based on some deep research into shooting cast 243).

I should note this is a Rossi gun. 1:10 twist. Needless to say, the lower charge rounds 13-16 were dismal. It dawned on me that the twist rate may be my handicap. I did not see any key-holing, but you could tell there is some major issue. I am still going to play with the higher end loads, 17+(will be loading up to Lymans max of 20.5), but I am curious what others have found out with this boolit in a 1:10 twist.

Would a faster powder, slower powder be the ticket? I don't want to rule out the boolit completely because of the twist rate, as the 17 grain charge seated long(only .243" of boolit in case neck) did group 'reasonable' at 100 yards.

But that is one other thing I question with this, seating length. When people have loaded this boolit, did you all play with COAL at all? I tried 3 different lengths, one book spec as listed in the lyman manual for this boolit. One a little bit longer(not sure where I came up with the length). And the last was by the old way of putting at least the diameter of the boolit, .243", inside the case.

The last one seemed to shoot the best. Its of course going to be the closest to the lands. Rossi's have notorious long throats. I have tried it, but cannot remember(will test tonight), but I could reach the lands with this boolit, but not much would be in the case. Guess I should have measurements before asking for advice....

I think I am going to try some Unique loads also, just for good measure. Truly all I am looking for is a plinking load for him, that can keep the holes in a 2" square at 100 yards, so he can have fun on Christmas with my boy who will be shooting his new gun.

One last thought/question. Would a shorter boolit, like the NOE 75 grain be worth a shot even though it would have a HUGE jump to the rifling in this particular gun?

Sorry for the long ramble, thanks for the help in advance. There are just so many different things to try I feel kind of overwhelmed at this point and still have one more gun to get shooting good after this one is done.

[JWFilips]

My RCBS 95 grain boolit in my .243Win Ruger 77 shoots very accurate with 16 gr 2400 ( also 10.5 gr Unique -no fillers)

[newton]

I believe the M77 has a 1:9 twist. That is probably why it shoots good. I have heard that 16 grain mark many times, and now I am wondering how many of them have a faster twist than 1:10.

I've been digging and I think my problem does end up with the twist rate. I am going to try and push them a little harder, I am thinking that I stopped short of where I need to be with the 18 grain load. I am not getting any leading so far, so the powder coating is doing good for me, so maybe I'll just test its limits.

I know your M77 is far superior to the Rossi gun, so there might not be much comparison, but did you have to play with the OAL at all? Do you know how far away you are from the lands?

[quilbilly]

My wife's Mossberg 243 is a real tack driver with an 87 gr. boolit and 10 gr of Unique.

[newton]

Thanks guys, any ideas what 10-11 grains of unique will push these boolits too? From what I have read, and the cast bullet load manual, they do best around 1800-2200 fps. Of course, it makes me scratch my head when I see they list loads in the 1600 fps range as "potentially most accurate".

Lymans just doesn't list any data for Unique and the 243.

[JWFilips]

I believe the M77 has a 1:9 twist. That is probably why it shoots good. I have heard that 16 grain mark many times, and now I am wondering how many of them have a faster twist than 1:10.

I've been digging and I think my problem does end up with the twist rate. I am going to try and push them a little harder, I am thinking that I stopped short of where I need to be with the 18 grain load. I am not getting any leading so far, so the powder coating is doing good for me, so maybe I'll just test its limits.

I know your M77 is far superior to the Rossi gun, so there might not be much comparison, but did you have to play with the OAL at all? Do you know how far away you are from the lands?

I develop "all" my cast boolit rifle loads with the boolit touching the lands. You are correct…. my rifle is 1:9 but those 95s should work well with a 1:10 also. My suggestion:Go to a faster powder, don't crimp, seat long. Fire from a steady rest & don't magazine feed ( load one shot at a time ) see if this is an improvement
You never said what you are sizing to? I shoot .246" and can get away with .245" anything less and no accuracy

[MarkP]

I am shooting the RCBS 95 & NOE 75 out of a 1:10" Kimber Montana; First loads were with a full case of Trailboss with great results. Everything I have tried has performed very well; RL-7, IMR 4227, SR-7625, Red Dot. I pushed a few to probably 2,500 ish with 32 gr of RL-15. Both are made from re-claimed shot plus a few sticks of lino probably in the 15 bhn range. Training rounds for kids, they will burst water filled bottles.

Going from memory I think the bore ride sections are 0.239" and will lightly engrave just a little at the radius tangent point when chambered.

The NOE 245-105 shoots soccer ball sized groups at 75 yds (4-5"), I bought the mold assuming the Kimber had a 1:9" twist bbl.

[newton]

I am sizing to .244". The barrel slugs at a very tight .243". I guess I could try opening the die up another thou.

I had my wife get me a nice solid shooting rest a few years ago, love that thing.

Not sure on the bhn, but they are hard. WW, with lino added, water dropped, and powder coated. I am not getting any leading, and I doubt I am pushing them hard enough at this point for them to be stripping.

Thanks for the replies though, makes me have a bit more confidence going forward.

[newton]

More testing to come, darn short days, but needless to say Unique is what I'll be testing with. I shot the loads I had waiting, 17 grains in a couple different OAL. For 4227, that is the spot if I wanted to waste time honing in on it. I doubt I could ever get much better than 2 1/2" groups though. I then loaded some with 19 and 20. Groups got larger and larger. Same as the lower charges that slowly closed up as I approached 17 grains.

Daylight fading i loaded up some 10 grain unique. Went to look at the target and saw a few more holes than I had shot. Then I realized they were hitting quite a bit lower than my scope setting and saw the tree limb in front of my target. But the interesting thing was the hits were quite close together.

So with the last mins of daylight left I loaded 3 more rounds - very quickly - and shot a 1 1/2" group. Quite a bit lower than POA, but I have not messed with the scope much waiting to see if I could get a decent load to group.

the scope was zeroed at one point for the hunting rounds, but since had changed when I replaced the rings. Needless to say, I'll work on this load now.

Honest opinions here, would it be ok to try 11 grains? Maybe 12? I am seeing no pressure signs with 10 grains. I just am curious if I could raise POI a little. They are definitely hitting 3"-4" lower than the 4227 loads.

My suspision is this, the boolits are needing a heavier smack to set in good. They might not be as good as the 10 grain load, but if it's safe to try I'd like too and see the results.

[newton]

One more question for tonight. How far out have you all ever seated a boolit? If I seat this far out I am almost touching the lands, not quite, but almost. I had been seating them, the longest OAL I tried, up to the base of that second lube groove. Which, getting about as close as I can get, a .075" jump to the rifling. I'm sure at this OAL I'm within .020" if not closer.

[newton]

Ok, I lied, one more then I'm done tonight. I don't know if my boolits are all just a little bit different size or what but I did the same experiment I did to find this length and it turned out different. Marked the boolit, and the neck, and put it in the gun. Got this.



Only different is i sized this case, then seated the boolit, then applied a light crimp with FCD. The gun had resistance closing and actually pulled the boolit some.

[MarkP]

Your rifle has an usually long throat.

[str8shot426]

Quite a long throat, I get great groups with 10 grains of unique. Seated in the rifling. Mine is a NEF single shot with a short throat. My gas checks are down in the case a bit. They do shoot well but are not barn burners by no means.

[JWFilips]

Looks like your bullet pulled out of the case on extraction ( Unless it could possibly be that long a throat)
How are you expanding you cases to seat the boolits. Factory dies are going to be too tight and you'll squash the lead You need to get at least an M die or better yet a Custom m-die expander or similar. Cast boolits in .243 do not take to j-bullet dies.

make up two dummy rounds but "do not crimp" seat them long. load them carefully into the chamber so they don't bump the nose of the boolit anywhere on the way in. Slowly close the action ...then open the action very slowly and carefully eject the shell into you hand.
Do the same with the other. Now measure the OAL they should be similar.
If the case neck has just enough tension ( not jacketed tight) to hold the boolit the action will push the nose into the lands and the case will give enough to let the boolit slide back into the case . If your alloy is hard like you said it should not stick in the lands and should come out clean with light marks where it touched. If it is working right the 2 dummy rounds should be the same OAL. ( i don't do powder coat so I can't vouch for how it will react on boolit extraction)
If they are not I would go to the traditional way of measuring which is drop a boolit into the chamber and lightly bump it into the throat with a stick. Hold it there and insert a cleaning rod down the muzzle until it touches the nose of the boolit without moving it back Mark the rod at the muzzle as accuratly as possible. Knock the boolit out of the gun Put the bolt back in and close it. Put the rod back in the muzzle until it touches the breech ...& mark it again. The distance between the two marks should be you near max OAL

[newton]

Yes, its a Rossi. These guns, ESPECIALLY the 243, are known for their very long throats. Just a quick google search will turn up countless threads.

What is interesting is I tried what you said JW, and when I closed it very softly I got the OAL in the first picture above. I did this a lot of times, 10+ at least. In the first picture, I did this with a fired case in order to have ample room for the boolit to slide into the neck without too much resistance. There was enough resistance, but not too much, that each time I placed the boolit to just where the gas check was inside the mouth, the boolit would be set back to where you see in the first picture.

Then, to see if the die would seat the boolit straight with only putting this much of it into the neck(and to verify function once again), I took the case, neck sized it, flared the mouth, seated the boolit, then used the FCD to just remove the flare not put a crimp on it. I did use another boolit I am pretty sure, because the gas check came off the first one when I removed it. Then I put the magic marker on it to just see if I could see the land marks.

Two things are possible. The powder coating is pretty slick for one, so in the first try, without the marker, it could have just been slipping in and out. And when the marker was applied, which does impart some 'stickyness', it could have been enough to grab it.

Second is the powder coating could have been a touch thicker on the second boolit. I HIGHLY doubt this as the case as they both looked similar and weighed the same.

One thing I have done is after seating my boolits, taken them back out and measured the diameter to see if the neck sized them down. I have done this many times, just to make sure, and the neck never sizes them down past .244".

I will try the OAL with a rod measuring method. I have done that on other rifles and had completely forgot about it. Thanks for reminding me.

I think its a powder issue to tell you the truth. I think that the Unique load will be fine. I just thought that I would try a different powder, try to get as much velocity as possible(to have a closer trajectory to the hunting rounds), and save my Unique for my pistol and 30-30 rounds where it performs great. But truthfully, a few hundred rounds for my nephew is not going to set my reserves back too much.

I did measure the marks the lands left behind, and if I set the boolit back that much more - theoretically making it just kissing the lands - then it will be sitting at the OAL that I had been using and getting the better groups with, which also puts the boolit base even with the bottom of the case neck.

I'll be curious to see what speed they are going at with the Unique load. Maybe with a 200 yard zero with the hunting rounds they will hit zero at 100 yards.

[newton]

So, anyone used 11 grains Unique with this boolit before? I see on castpics that 11 grains is listed as max, but they also list that it is 95 grains. Finished boolit weight of mine are 101.2 grains.

[Larry Gibson]

newton

I see you're PCing the bullets(?). Are you GCing and sizing the RCBS bullet at all?

Larry Gibson

[newton]

Yes, both. hair over .244"

[newton]

So after reading an article, I am not too sure that the issues I saw with 4227 are not coming from different powder positions in the case. Not that I want to use it over Unique per say, but the curiosity is what it might perform like if the powder were ignited in the same part of the case each time.

Knowing full well that my nephew will not take this into consideration, there would only be one other way of ensuring this. Using polyfill. Has anyone used pollyfill with 4227, in 243/308? I have only used it one time in 30.06, but it worked fine in that situation.

[JonB_in_Glencoe]

One more question for tonight. How far out have you all ever seated a boolit? If I seat this far out I am almost touching the lands, not quite, but almost. I had been seating them, the longest OAL I tried, up to the base of that second lube groove. Which, getting about as close as I can get, a .075" jump to the rifling. I'm sure at this OAL I'm within .020" if not closer.

my 2¢
I "had" a older custom mauser Benchrest rifle (243win) with a long throat (Shotout I suspect). I have the NOE 75gr and couldn't seat the boolit out far enough to touch the lands,,,and never got that boolit to shoot. I also had a Lyman Lovern style 87gr. That shot "OK" seated to touching the rifling...it was still seating out pretty far. I had the 105gr on order through the GB, before NOE took it over, but I didn't get the mold til after my auction this spring...sold the gun at that auction.