Need help with 450 Bushmaster loads.

[MudBug]

I've shot some inexpensive plated bullets through my 450 and they seemed to handle the velocity ok. not great accuracy, but they didn't seem to be coming apart.

[17DoubleE]

rpm vs diameter

I'm not sure that I see the twist as being an issue as much as bullet construction, or maybe some factor not yet considered? 230 grainers at 3,000 fps out of pitted bore's 16 inch twist are only spinng at 135,000 rpm. This is only getting to the top end of cast bullet accuracy rpms. There are all kinds of folks winning bench rest & high power matches, or popping PDs with jacketed bullets spinning over 200,000 rpms.

The only time I ever experienced the gray dust cloud, and no holes in the target, was trying a handful of varmit grenades out of a 8 twist .220/06. They were spinning well over 300,000 rpm before going "poof".

Could it be that the average 230 grainer, designed for .45 acp, just can't handle the pressure? I'm also wondering if the self defense designs, with the big hollow points and striated jackets might be more prone to coming apart than a regular cup and core hunting construction bullet? It wouldn't take but one little petal going just a wee bit out of concentricity to make a flyer.

I finally got my lower in and by the weekend I'm hoping to run some 250 grain Sierras to break in the barrel a bit. I don't think I'm gonna hit 3,000 fps though

BD

I wonder if the diameter of these bullets (.452) and the resulting surface speed wouldn't cause them to come apart at the velocities smaller calibers can endure. The 'ol pi r^2 thing...?

[GunNut]

The problems I had were the TMJ or copper clad bullets. Their jackets are not much more than copper foil. I had consistent failure with these! I have not used any hollow points. The heavy crimp in the 284 case could have been the problem. I'm now using sierra's #8815 230gr. .4515 FMJ and Zero's #123 230gr. ..451 FMJ in reamed 284 cases with excellent results. any questions? just P.M. me. Thanks again All!

[Wildcatter]

You guys are such thinkers, to your credit.

If I might be so bold, I might start you thinking like and R&D Specialist that wants to get to the race track sometime this Decade. What I am about to discuss will have holes in it that the Ballistic Engineers on the other boards will trash. They have their agenda and I have mine. They take years to develop something new; I do it in days/weeks. I personally am not interested to take more than one hundred years to develop perfection in the 30-06, to finally conclude that what is needed is a +p+ loading.

Having said the above, DO NOT TAKE ANY SAFETY SHORT-CUTS, if you do not know the safe Reloading Practices, then learn them, this particular thread is contributed by, for the most part, by experts. And as such, much is not said in the post here that is only understood by many of the more experienced readers. This is why many ask basic questions, they are trying to understand what might be un-said. It then becomes our duty to not to ridicule, but to educate and believe me; I am not so learned that much of what you gentlemen discuss here gets my brain cells working real well. I am considered an extreme expert, in many fields and as such, I am the first to acknowledge just how ignorant I really am. So you, dear reader, realize that we are not the last word here and that you have a grave responsibility to keep yourself and equipment safe.

Here are a couple of formulas I worked up that might help the current thread banter.

Barrel Twist/Revolution Formulas

Formula #1 - MV X 720/Twist Rate = RPM
Formula #2 - MV X 720/RPM = Twist Rate

Example:

[pitted bore]

Wildcatter-

PM sent.

--Bob

[GunNut]

All I can say is "WOW"!! You guy's are something else! Your buiding Clocks! and all I want to know is What time it is!

[GunNut]

OK Guy's a quick survey here!
What loading software are you using? If any.

Myself?......None at this time

[Slash2]

OK Guy's a quick survey here!
What loading software are you using? If any.

Myself?......None at this time

Software? Would that be the fabric on the seat of my pants?

[GunNut]

LOL! I guess that's what wear doing here! Flying by the seat of our pants!

[BD1]

I think the question is more; What chronograph are you using? Ballistic programs are just estimators, and the estimations are not real useful until you have some real world feedback to judge them against. A chronograph is the only real option, outside a ballistic lab, for data to correlate to the model.
Chronys can also be had for less $$ than a decent ballistic program.

I do have Quickload. The model worked pretty well up through 37 grains of Lil Gun behind the Nosler 250 grain JHP #43013 @ 2086fps. Unfortunately above that, 38 to 40 grains and up to the 2,300 fps level, my velocities started deviating upwards from the model significantly. Accuracy also was not great with those 30 shots resulting in a 3 1/2" group.

I need to try a few more different powder and bullet combinations before I make an attempt at tweaking the model to suit my gun. The issue here may be powder. I have plenty of primers but Bass Pro was completely out of H110, 296, Lil Gun and they don't carry the VV line. The only powder I have here in quantity anywhere close to this burn rate is Surplus WC680, (1680). I'm saving that for last as I'm expecting it to crud up the gas tube.

Anybody in Upstate NY want to trade a pound or two of 296, H110 or Lil Gun for 1,000 Rem 7 1/2's ?

BD

[Wildcatter]

Everybody has an opinion on software/hardware, I like these guys and when you speak to the owner mention my name and be ready for serious customer service. RSI was recommended to me by some highly respected end users some of them no less than the Engineers at Remington. Spend some time reading at this site (some of you will spend hours here) and it will open your eyes to a world few know and make your 450 Bushmaster loading process much easier and your head, well more informed..

http://www.shootingsoftware.com/index.htm

Safety First..t

[jagermaster]

BD1
If you have any small rifle primers I can help you out.
I have no need for other sizes.

I have a local shop that has lots of lil'gun.
I think they also have h110 but not sure.

[MudBug]

I made some changes to my 450b

Larue 9.0 FFHG (I hate the stock handguard with a passion)

It was sharing a lower with another rifle, now it's on a CavArms lower that I chopped just enough to install a grind-to-fit LimbSaver I had laying in my parts box and not change the LOP.

A TR21R that used to be on my Recon/3-gun rifle.

[BD1]

[BD1]

The text editor for this board is pissing me off. I can't stay connected long enough to type data in to it, and it can not even reproduce the line spacing from it's own editor to the post page. If I copy and paste data the editor rearranges it arbitrarily. I'll do the best I can to explain it. Real chrony data is to the left on the line, Quickload predition data is next on the same line. Next time I'll use { } for the quickload data.

BD