So this happened at the range.

Was at the range last weekend to test some loads. First went to test some 243 subsonic loads, first shot hit target, second shot went pop proceeded to load third round but no sign of impact of second shot on target. Thought to myself something isn't right here, perhaps bullet from second round is stuck in barrel. went to unload third round to check the bore, the case ejected with GC and powder still installed but no bullet, as you can see from photo. bullet was stuck in the lands and I had nothing on hand to remove it so that was the end of that load testing. Walked up to check the target and the second bullet had hit the hole from the first.
Attachment 174951

Second, I was also testing some 303 loads with lee 185-312 bullets lubed but no GC's with 8.5 grain of trail boss. 7 shot, 10 inch group with 4 keyholes at 25m. SHOCKING!!! After the first keyhole I removed the suppressor, checked for damaged, couldn't see anything and continued shoot without suppressor. What did I do wrong with my loads? Using lee bullets, no GC's? Any advice

Im not real experienced with cast loads but if your projectile is stuck in the lands and pulled out then your overall lenght must be too long and jamming the projectile into the lands?

Not quite enough neck tension perhaps. I've noticed the cast bullets are somewhat "softer", so if the OAL is a bit long, then they wedge into the lands quite easy.

Sent from my SM-G975F using Tapatalk

I seat my cast subs to the crimping groove and lightly crimp them.
Some people have reported better accuracy with crimping, but that doesn’t appear to be an issue here!

It’s standard practice to test subs without the suppressor first, to make sure they aren’t tumbling.

243 bullets are bore riders. Seated to crimping groove which is COAL. Did not crimp and I am suspecting there wasn't enough neck tension because I've made some dumby rounds that ejected fine.

Check the freebore of your 303 they are notorious for being eroded.
With the muzzle pointing down drop a projectile in the breech and very lightly tap it with a rod or similar to make sure it's engage the rifling.
From the muzzle run a cleaning rod down till it touches the bullet Mark the rod at the muzzle with a sharpie felt pen.
Drive the bullet out and replace it with a dummy round with the bullet seated as you normally do.
Put the rod down the muzzle again to touch the bullet and mark the rod.
Measure the distanice between the two marks, that's your freebore.
I had a martini enfield that had 2 and a half inches of freebore couldn't shoot cast or boat tail jacketed bullets well enough to hit a flock of barns at 10 yards but flat base jacketed bullets managed 6 inches at 100.
With excessive freebore cast bullets chatter around and can't seal effectivly paper patching can help if you patch to about 4 or 8 thou over bore size that accomodate the eroded throat.

hmmmm makes a fella wonder if a hollow base,like older designs had would have merit......a GC would make matters worse not better I guess too.pretty sure Robert can size the projectiles a bit larger too.....

Quote:

---

Originally Posted by Micky Duck

hmmmm makes a fella wonder if a hollow base,like older designs had would have merit......a GC would make matters worse not better I guess too.pretty sure Robert can size the projectiles a bit larger too.....

---

These aren't Roberts 303 185's. His 210's shoot awesome, I'd really love some more.

Doesn't really help but I load the Sierra 75gr HP with 6.7gr of Trailboss for a mate's 243. Deadly quiet and accurate. He head shot a few pigs at the back of the farm with it now - through the skull, into the brain, lights out. No need for cast bullets I recon.

Quote:

---

Originally Posted by JaSa

Doesn't really help but I load the Sierra 75gr HP with 6.7gr of Trailboss for a mate's 243. Deadly quiet and accurate. He head shot a few pigs at the back of the farm with it now - through the skull, into the brain, lights out. No need for cast bullets I recon.

---

Nice. I've loaded some Nosler 55gr hollowpoints with 15gr of trailboss, blow large holes through whatever they hit.

Your .312 bullets are undersized by at least 2 thou. Slug your bore and use 1 to 2 thou over .

Greetings,
Mike Venturino, who writes for Handloader and Rifle has said that a cast projectile that is designed for a gas check will likely shoot poorly without one and I think this may be at least part of the problem together with the under size projectile. Standard groove for the .303 is .314 inches and many are much larger .
GPM.

When loading for subs you start high and work down, not like supersonic loading.

Did you do this?

So dealing with the 303 first, either (a) make a chamber cast or option (b) get a case, fill it with a harder lead say 4mm from the top, let it set (always helps!) then get a projectile at least a few thou over bore diameter……..and here’s why, ive had a good number of 303’s with a massive difference in actual bore size, remember that the tooling dies wore over time and there were variations, big variations, back to option (b) place that fatter projectile into the neck of the case, place it lovingly into the breach and close the bolts, here’s the trick, if it requires some extra love to get her home that’s all good, to really finish the job, get the cleaning rod, take the end jag of and put the rod down the barrel against the projectile, keep the bolt closed and tap the rod, you are trying to squash the projectile so it fills out against the groove and lands, open the bolt and push the projectile out…

Here’s the fun, measure the diameter, now aim for say 2 thou over for THAT rifle as your sizing, now repeat with out ramming the rod down the bore, this will give you the ability to understand seating depth, also keep the round as you can do the same for other 303’s

You want the projectile to engrave rifling……but also with the ability to cycle the bolt and have the round eject…..with projectile! I always kept a cleaning rod with me for the whoopsy moment.

The next aspect will be playing with the most gentle approach to applying neck tension, also I can’t recommend getting a case neck flaring die to help in the process…..

Update: Got GC's for the 185-312's. Loaded up some rounds with 12gn AP70N, 29gn of AR2208 and 10gn trailboss, shot to 50m, .8'' group with AP70N, 1.6'' with 2208 but might of been pushing them too fast and 5'' group with trailboss but might of had a flyer. No keyholing.

You would be very fortunate to find a .303 with a .312" barrel even a brand new is more likely to be .313"
Cast bullet generally don't like being jammed in the rifling a few thou off works best with most of them and a crimp is a good idea
if there is a groove for the purpose use it, If not just turn the mouth of the case in a small amount too much can damage the bullet
don't use the Lee FCD it makes a mess of lead bullets from what I have seen.

@shooternz
Attachment 182406

Quote:

---

Originally Posted by Three O'Three

@shooternz
Attachment 182406

---

Yes they look ok, just don't jam them too tight into the lands if you have to open the bolt you could extract a bullet
I seat mine just a little off, Both my 6mm BR and 6mm Rem I seat the bullet so the lube groove is inside the case
and have a light crimp on to the driving band,
What is the accuracy like with the .243? I am prepping some cases for the 6mmBR it's taking a while I have ream the necks
to get rid of the donuts from neck turning got 25 finished today hope to get them loaded and out to the range in the new week