Need help with 450 Bushmaster loads.

[ar15barrels]

The trimmed case wall at the mouth seems to be about .001 or so thicker, although I don't see it when I mic them out, but when seating the bullet with the 450 die, the alignment sleeve often scrapes a little brass off of the case and sticks when retracting it from the die.

Do you have a tubing micrometer for measureing case necks?
You can't really get good measurements using a caliper.

I suspect that your case necks are thicker towards the base of the neck and that the cases would need to be reamed or turned to get consistent neck wall thickness.

[Slash2]

Do you have a tubing micrometer for measureing case necks?
You can't really get good measurements using a caliper.

I suspect that your case necks are thicker towards the base of the neck and that the cases would need to be reamed or turned to get consistent neck wall thickness.

That's my guess too, but at this point I'm already in over my head. I don't have the tools, and even if I did get the cases right I'd still have to come up with a load that works without killing myself.

I think given my shortcomings I'd be better off sticking with my factory cases till they wear out and then buy more factory rounds. Someday they'll have to start selling cases and releasing load data, till then I'd rather let someone else be the scout, they can take the arrows in the chest instead of me.

Thanks for your help Randall, you gave me a good place to start. I think next time I'll buy something in a common caliber, but this one is sure fun to shoot!

[Wildcatter]

I'm giving up on using trimmed down W284 cases, at least till someone smarter than me comes along and tells me exactly how to make them work.

But, here's what I've experienced so far:

The trimmed case wall at the mouth seems to be about .001 or so thicker, although I don't see it when I mic them out, but when seating the bullet with the 450 die, the alignment sleeve often scrapes a little brass off of the case and sticks when retracting it from the die.

The large rifle primers increase the pressure a lot. I stepped down 4 grs. of powder from my other loads (34 grs H110 from 38 grs.) and I still had a moderately flattened primer on my first round. So I tried my next .5 gr. step up and blew the primer out of the pocket!

Back home, load six 32 gr. rounds. Next day at the range (the range fees alone would cover buying factory rounds instead of reloading these things) I hand load one in the chamber and fire, primer looks fine, load four into the mag, failure to feed, drop the mag, with effort pull the partially closed bolt back and extract the stuck round. Insert mag with 3 rounds, failure to feed. Again struggle to extract the stuck round and say f**k it, I give up, it's not worth it.

I'm sure I'm doing something wrong, but this is like walking into a dark room that you've never been in. You know there's a light switch in there somewhere, but for all you know there may an open bucket of paint by the wall, a coffee table with all of Aunt Martha's antique glass curious and a sleeping cat on the floor. Will you find the light switch before or after the other stuff?

Any insights, both helpful and critical are welcome. I mean we're talking eyes, hands and gun being at stake here and I don't know where the light switch is.

Until you sort out your reloading process you'd better stop shooting your reloads.

First of all, your .001" thicker necks is nothing. Putting on a heavy tapper crimp will size the outside of the case perfectly and insuring proper feeding into the chamber.

Second, measure your cases and please report back the length of the cases that are sticking. I don't want the length standard you used, but I do want to read the length of the actual cases that stuck. Until I learn more it sounds like your case length is long. I have a couple of other issues, but one at a time here.

[Slash2]

Until you sort out your reloading process you'd better stop shooting your reloads.

First of all, your .001" thicker necks is nothing. Putting on a heavy tapper crimp will size the outside of the case perfectly and insuring proper feeding into the chamber.

Second, measure your cases and please report back the length of the cases that are sticking. I don't want the length standard you used, but I do want to read the length of the actual cases that stuck. Until I learn more it sounds like your case length is long. I have a couple of other issues, but one at a time here.

I think I see what you're getting at, the case being too long and sticking at the end of the chamber, which if I'd provided more info about where mine are sticking that might not seem like the problem.

I can drop a round in the chamber and close the bolt no problem, even those that have previously stuck, but if I'm feeding them from the magazine the bolt will not fully close, it still has about 3/8" to go. The forward assist doesn't move it forward, it probably just jams things more, making it stuck enough that I have to use some force on the charging handle to eject the round.

And you are right about the crimping. I crimped my first rounds to the same outside dimension as the factory rounds. After firing a few (all hand fed into the chamber) and seeing the signs of excess pressure, I pulled the bullets on the remaining cartridges. The crimp was excessive, leaving deep marks on the bullet. This lead me to believe I had over crimped and that was why I was getting the high pressure. So I used a light crimp plus 2 grs. less powder on the ones that stuck. No sign of excessive pressure on the one that fired but enough of a pain in the *** to make me decide to pack it in.

As I list these things out I can see that I'm changing too many things at a time to get this dialed in, I guess gas prices, range fees and time out of the my day are exerting excessive pressure on me.

[Wildcatter]

[ar15barrels]

I can drop a round in the chamber and close the bolt no problem, even those that have previously stuck, but if I'm feeding them from the magazine the bolt will not fully close, it still has about 3/8" to go. The forward assist doesn't move it forward, it probably just jams things more, making it stuck enough that I have to use some force on the charging handle to eject the round.

This is THE classic "short of headspace" symptom.
If you drop the cartridge into the chamber and let the bolt fly home, the kinetic energy stored in the bolt carrier group will SIZE the cartridge in the chamber.
If the same cartridge will NOT let the bolt close from a mag, that's because you burned off some of that kinetic energy in getting the cartridge out of the magazine and around the corner into the chamber.
The 3/8" or so of carrier is the locking/unlocking travel.
When you drop a 5.56 "field" gauge in a 5.56 barrel, that's what you are supposed to see because the bolt should NOT close on a field gauge.

The pressure signs ALSO point to the case mouth getting crimped against the bullet.

Does the 450 headspace off the case mouth?
If so, both symptoms could be related to cases trimmed too long.
Some precision measurements of chamber and case length may be in order.

[Wildcatter]

This is THE classic "short of headspace" symptom.
If you drop the cartridge into the chamber and let the bolt fly home, the kinetic energy stored in the bolt carrier group will SIZE the cartridge in the chamber.
If the same cartridge will NOT let the bolt close from a mag, that's because you burned off some of that kinetic energy in getting the cartridge out of the magazine and around the corner into the chamber.
The 3/8" or so of carrier is the locking/unlocking travel.
When you drop a 5.56 "field" gauge in a 5.56 barrel, that's what you are supposed to see because the bolt should NOT close on a field gauge.

The pressure signs ALSO point to the case mouth getting crimped against the bullet.

Does the 450 headspace off the case mouth?
If so, both symptoms could be related to cases trimmed too long.
Some precision measurements of chamber and case length may be in order.

[Slash2]

Ok Slash, it looks like you may have a number of problems, all related to the hand loads. The 450b is notorious for absolutely great feeding, so we’ve got to look at the processes. If you want the help you'll need to answer those two questions.

What case length standard are you using and what is the actual length of the sticking cartridges?

I have years of experience with the 45 PROFESSIONAL and can give you a leg up, if you want it.

Please forgive me for sounding hard, I mean no offence.

P.S. Where are the cartridges jamming? Without knowing, I suspect the edge of the hollow point might be catching the edge of the chamber. If you are not sure, try inducing the jam again and get those eye balls in there and report back.

My factory cases are 1.691" to 1.693" My trimmed 284 cases range between 1.694 and 1.691". I was using Rainier 250 Gr. flat points that are .452 in dia. and my over all length when loaded was 2.1".

I can't tell you where on cartridge they were sticking, I destroyed the evidence, but I am willing to load up a couple more of the annoying bastards for the sake of science.

And BTW, you'd be hard pressed to offend me, I'm playing with fire without the proper skills, I figure I'm fair game for a little reasonable abuse.

[ar15barrels]

I can't tell you where on cartridge they were sticking, I destroyed the evidence, but I am willing to load up a couple more of the annoying bastards for the sake of science.

Apply sharpie marker to the outside of the bullet and case.
Chamber and then extract.
The sharpie marker will get removed from the offending areas.

[Slash2]

Apply sharpie marker to the outside of the bullet and case.
Chamber and then extract.
The sharpie marker will get removed from the offending areas.

The offending area is the case at the base of the bullet.

The factory case diameter at the mouth with a seated bullet is .478" with the case diameter .481" at the base of the bullet. I was able to crimp the 284 cases to match the factory .478 diameter, but at the base of the bullet the 284 case swells to .489". That's where it was hanging up.

[ar15barrels]

The offending area is the case at the base of the bullet.

The factory case diameter at the mouth with a seated bullet is .478" with the case diameter .481" at the base of the bullet. I was able to crimp the 284 cases to match the factory .478 diameter, but at the base of the bullet the 284 case swells to .489". That's where it was hanging up.

The solution is either to neck ream (requires a custom die/reamer, or neck turn.
Either method will be able to reduce the neck wall thickness so that it fits the chamber better.
Neck turning will also produce necks that are more concentric.

[bla]

To be clear on the crimp. you cannot crimp ( roll crimp etc.) the 450 Bushmaster. This cartrige headspaces on the case mouth.

[bla]

I have also had feeding problems with the 450 B. I have found that all my problems have been the result of unburned powder in the chamber. Are your loads burning clean and consistant. Have you cronographed your loads. This is the best way to detect inconsistant burns.

[Slash2]

To be clear on the crimp. you cannot crimp ( roll crimp etc.) the 450 Bushmaster. This cartrige headspaces on the case mouth.

That's right, it does headspace on case mouth. The factory die set includes a roll crimp with the seating die and a separate taper crimp die. I've been using the taper crimp on the smooth sided bullets, however I have some bullets with a canulare - canlura - canulalure- whatever, groove, and I have put a slight roll crimp on those.

[Slash2]

I have also had feeding problems with the 450 B. I have found that all my problems have been the result of unburned powder in the chamber. Are your loads burning clean and consistant. Have you cronographed your loads. This is the best way to detect inconsistant burns.

I had problems with unburnt powder too when I was starting out using real light loads, once I got closer to the hotter factory loads it cleared up, but I did see a little unburned powder the other day after firing one of my lightly loaded 284 cased rounds.

I've cronographed my later loads at from 1850 to 2175, I don't know what the earlier ones did.

However, I'm not sure that was the real cause. Yesterday I seated some bullets in my 284 cases and marked them up with a sharpie to see where they were jamming. The first one feed just fine from the magazine, but when I ejected it I noticed the bullet had been pushed half way out of the case by the force of being shoved forward and then suddenly stopped. Now I'm wondering what problems that may have caused!

Now let me make one thing clear, I'm not blaming the 450 Bushmaster at all, it feeds and shoots reliably with factory ammo, plus it is accurate as hell. I'm sure all my problems are related to my lack of experience, compounded by trying to work up loads for a cartridge that is new and doesn't have much data available.