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Neverhome
02-28-2018, 01:37 PM
First post here. I've been lurking for quite some time and learned a great deal from everything I've read. So thank you!

I recently started casting for a MGM 16.25 inch barreled Encore in 357 Magnum. It shoots jacketed amazingly well and the LEE 358-158-RF into very pleasing groups.

Well I decided I wanted to try something heavy, slow, and quiet so I ordered a NOE 360-225 SWC. Here's where the problem starts...

I literally miss a 18 inch target at 50 yards with most shots. I've tried the bullet with 3 different powders, many different speeds, and 2 different alloys. Haven't remotely begun load development because I can't hit the target. The shots that do hit are rarely clean SWC holes. No keyholing but perhaps a slight oblongness maybe. Not oblong enough that I'd have even noticed though unless I was looking for a problem.

I have other NOE molds and their push through sizer. Sizing the 158 and the 225 to .359.
Barrel is 16 twist. The actual rifling of the barrel is only approx. 15 inches long obviously because of the chamber so best I can figure with a tight cleaning rod is it's AROUND a legitimate 16 twist barrel. Bullet is plain based and right at 0.95 inches long.
I've tried many different subsonic loads and 1 super. Sub was with Clays, Trailboss, and middle of the road H110 loads. Super was with a higher H110 load. All shot exactly the same just with varying levels of noise. I only tried supersonic after all the other subsonic loads failed to reliably hit the target. I could try other powders obviously but I don't want to keep wasting components if I can't even hit the paper.

I'm at a loss here! My first instinct was twist rate but I'm getting close enough to the advertised 16 twist that it doesn't add up. If my math is right this bullet should have ample stability in anything in the neighborhood of 20 or less.
I did slug the barrel but what an absolute pain that was to measure. 5 groove rifling. I don't remember what I got but I know I didn't trust my measurements. Neighborhood of .356 I THINK using an aluminum can shim wrapped around the bullet and then subtracted out.
I've also captured numerous bullets in putty. No sign of gas cut bases or widening rifling marks. Bases all end up slightly concave with sharp trailing edges. Gas seal looks good to me. I even seated bullets and then pulled them to see if my brass was overly sizing them. Difference was only 0.0005-0.001 and as I said no gas seems to be leaking by and there doesn't seem to be any skidding.

Alloys used have been straight Lyman #2 and 50/50 Lyman/pure. Pan lubing with mix of floor wax, Vaseline, paraffin, and a little synthetic motor oil. No leading to speak of.

Anyone got any ideas?? Like I said I'm at a loss at this point.

earlmck
02-28-2018, 02:22 PM
That boolit isn't stabilizing for you, no matter that your calculations say it "should" stabilize. And it is possible you can't drive it fast enough to stabilize in that barrel. Maybe time to add to your barrel collection with a 358 Winchester?

MT Gianni
02-28-2018, 03:03 PM
http://www.lasc.us/Fryxell38SWC.htm

http://357shooter.blogspot.com/2013/02/responding-once-twist-rates-gas-checks.html

Here is some reading. The 358627 I have does real well in a Handi rifle rechambered to 357 max. I have never felt the need to measure twist rate in it. I understand it was offered in either 1 in 15 1/2 or 1 in 18. You may try it with wadcutters to see if bearing surface is long enough to mess with it. An adequately sized bullet should show some tearing or odd marks if it is keyholing. I might try as cast, hand lubed or LLA in a moderate load of a medium powder to eliminate a size issue.

Neverhome
02-28-2018, 03:41 PM
earlmck, I can definitely push this bullet a little harder. There are no apparent signs of excess pressure or velocity on captured bullets or cases so I can up the charge if speed seems to be the issue to stabilization. I can give that a try with a small sample as I'm tired of wasting components at the range. Can't recover my lead there.
I've considered myself adequately versed though on the topic of stabilization til now. Antiquated Greenhill calls for about a minimum of 20 twist for this bullet and Berger's calculator shows optimum stability all the way down to 250 ft/s but also states that the calculator UNDER estimates the stability of flat based bullets so it SHOULD be golden.
I'm certainly not arguing by bringing these up but I truly don't understand why it would be unstable. It may very well be but I'd like to understand why.
MT, Thanks for the reading material. This bullet as I'm sure you probably knew is the NOE copy of 358627. I'm sure you pushed harder in the Max. I may have to try pushing it harder as earlmck suggested. As far as size goes, as cast is .361 and I am sizing to .359. The 158s shoot great at .359 and neither bullet when captured shows any skidding or blowby that I might expect if the size is too small. I'll certainly give as-cast a try though. I'm not sure what you mean about trying a wadcutter. Can you expand?

runfiverun
02-28-2018, 08:44 PM
never shot a calculated bullet before.

push it as hard as you can if it's still messed up quit wasting your time and move on to something else.

dubber123
03-01-2018, 01:17 AM
never shot a calculated bullet before.

push it as hard as you can if it's still messed up quit wasting your time and move on to something else.

I agree, stand on the gas a bit, I bet that helps matters.

Neverhome
03-01-2018, 07:32 AM
Got it. Thanks for the input so far. I intend to do as suggested and push the velocity up among some other much appreciated options suggested in a PM.

Now in the interest of teaching a man to fish instead of just giving him a fish, anyone have experience with or care to explain why a undamaged bullet that SHOULD easily stabilize in a particular twist doesn't appear to be in this one. I assume we are talking stability if everyone is suggesting pushing up the velocity. If that ISN'T what you all are getting at then please elaborate.
Everything I've read says this bullet should work regardless of my velocity. I won't be heartbroken if everything I read is wrong but I'd definitely like to understand WHY.

Hamish
03-01-2018, 08:42 AM
Neverhome,

As said, up the velocity, it will fly. My last note on 110 shows 15.1gr to be retested at some point with the 360-235 I shoot, but I settled on 14.0gr of 2400. (quite a bit more pleasant to shoot)

As Run and others have said "should", and "calculated", go right out the window when the trigger is pulled. Sometimes they won't stabilize at low speed, and more often than not, they will do well faster than the "calculations" say,,,,,

Please keep us informed of your progress.

Wayne Smith
03-01-2018, 08:59 AM
The Greenhill formula was created to use with artillery shells! Scaling it down adds many levels of error. It can only approximate, not give hard data. Use it as a guess but don't be surprised when your rifle argues with it. Believe the rifle!

Neverhome
03-01-2018, 09:07 AM
Is that is the MAGNUM??? Crimped in the top or bottom groove or at all? Asking cuz that sounds like ALOT of 110. Haven't worked with 2400 yet.

http://www.lasc.us/FryxellLyman358627.htm No mention of twist rates in this article but it does show good accuracy with low speed 38 Special loads. Well that just bugs me!

Thanks for the input guys!

Any other possibilities for yaw in a bullet that to my admittedly untrained eye appears undamaged?


Neverhome,

As said, up the velocity, it will fly. My last note on 110 shows 15.1gr to be retested at some point with the 360-235 I shoot, but I settled on 14.0gr of 2400. (quite a bit more pleasant to shoot)

As Run and others have said "should", and "calculated", go right out the window when the trigger is pulled. Sometimes they won't stabilize at low speed, and more often than not, they will do well faster than they "calculations" say,,,,,

Hamish
03-01-2018, 09:19 AM
I do not crimp my single shot loads, I try not to crimp much of anything. 12" MGM .357 Mag Contender bbl.

Yes, it was a *lot* of 110, but I was shooting gas checked and trying for maximum velocity with best accuracy at the time. I got close to 1700fps before I backed down to 1450fps with 2400 as I wanted to be able to shoot a bunch with it without hurting the next day,,,,,,,

One thing I noted, I don't use nickel cases anymore with heavy Contender loads, nickel will get you sticky cases long before any sign of pressure in plain brass.

Neverhome
03-01-2018, 09:23 AM
I'd trust the Berger calculator before Greenhill honestly but I find with the Berger calculator it indeed underestimated stability with flat based/cast bullets. I've had flawless stability with .22 flatbased using that calc with stability factors all the way down to a hair over 1.0. At about a 0.9 I had noticeable yaw on target. This was all with subsonic stuff but velocity is factored into that and all other modern calcs.

Trial and error is expensive so I feel like doing a little research and trying an apparently much maligned stability calculator is justified.

"OH MY GOD HE USED A CALCULATOR BEFORE HE BOUGHT A 100 DOLLAR MOLD!!!" ;)



The Greenhill formula was created to use with artillery shells! Scaling it down adds many levels of error. It can only approximate, not give hard data. Use it as a guess but don't be surprised when your rifle argues with it. Believe the rifle!

Neverhome
03-01-2018, 09:30 AM
Is your MGM chamber super tight? I bell my case mouths the tiniest bit I can and still get a bullet to sit on top. Barely visible bell with the naked eye. I still have to do a very light crimp to get the rounds to chamber. My TC 45-70 barrel wasn't nearly so touchy but also wasn't a "custom" barrel either. Could be the die geometry too I guess.
I have some nickel cases sitting aside but I don't do any load development with them. Thanks for the heads up on that.

bosterr
03-01-2018, 10:04 AM
I have 2 MGM 357 barrels in my safe, both 1 in 18 twist. When these barrels were made you had a choice of twist rate. At some time since, MGM stopped giving you a twist rate option, probably to reduce their barrel blank inventory. I don't think your twist rate is an issue here. Just the other day, I fired my 12 inch barrel at 100 yds. It wears a Bushnell 2 X 6 power scope. The forearm is a 2 inch wide custom flat on the bottom which matches the Hughes sand bag with a 2 inch groove. My load is Saeco's 180 gr. truncated cone (186 gr. actual) plain base boolit lubed with Carnuba Red and sized at .3585. Since I load these for several S & W revolvers I roll crimp on a Dillon 650. Powder is 13.5 gr. of WC820 which depending on what batch number burns somewhere between Accurate #9 and H110/296. I'm guessing velocity is around 1400 fps plus. That day I got a measured 8 shot 1 1/2 inch group and one flyer about 2 inches out at 100 yds. MGM barrels just down right shoot! I'll only buy MGM and SSK barrels now. I've watched my wife on too many occasions to count, with her 10 inch barrel,make a bullet hole in a blank piece of paper at 25 yds. to use as a target and proceed to send every shot thereafter into nearly that exact same hole. That's using the same model scope, the flat forearm and the Hughes bag.

Neverhome
03-01-2018, 10:23 AM
I'm very pleased so far with my MGM as well. Very accurate with everything BUT this one bullet.
I've casually looked for wider forearms but never pulled the trigger so to speak. I don't care much for the narrow stock one. Most of my background is recreational middle distance benchrest stuff so I enjoy a wide forearm. Where'd you source yours?


I have 2 MGM 357 barrels in my safe, both 1 in 18 twist. When these barrels were made you had a choice of twist rate. At some time since, MGM stopped giving you a twist rate option, probably to reduce their barrel blank inventory. I don't think your twist rate is an issue here. Just the other day, I fired my 12 inch barrel at 100 yds. It wears a Bushnell 2 X 6 power scope. The forearm is a 2 inch wide custom flat on the bottom which matches the Hughes sand bag with a 2 inch groove. My load is Saeco's 180 gr. truncated cone (186 gr. actual) plain base boolit lubed with Carnuba Red and sized at .3585. Since I load these for several S & W revolvers I roll crimp on a Dillon 650. Powder is 13.5 gr. of WC820 which depending on what batch number burns somewhere between Accurate #9 and H110/296. I'm guessing velocity is around 1400 fps plus. That day I got a measured 8 shot 1 1/2 inch group and one flyer about 2 inches out at 100 yds. MGM barrels just down right shoot! I'll only buy MGM and SSK barrels now. I've watched my wife on too many occasions to count, with her 10 inch barrel,make a bullet hole in a blank piece of paper at 25 yds. to use as a target and proceed to send every shot thereafter into nearly that exact same hole. That's using the same model scope, the flat forearm and the Hughes bag.

bosterr
03-01-2018, 10:30 AM
My very talented friend made mine. All our other custom barrels wear nicer, rounded forearms that my friend made as well.

I forgot to add, I use 70/30 coww and pure lead and water drop.

Larry Gibson
03-01-2018, 10:31 AM
Neverhome

What is the length of your bullet?

Neverhome
03-01-2018, 10:59 AM
O.95 inch

225ish grain depending on alloy.


Neverhome

What is the length of your bullet?

Larry Gibson
03-01-2018, 11:14 AM
Neverhome

Your NOE bullet should stabilize in a 16" twist to a very low velocity. Have you actually measured the twist?

You say it is PB bullet. Is that an actual PB mould or the GC mould sans the GC?

What alloy?

What lube?

Neverhome
03-01-2018, 11:29 AM
Actual plain based bullet.

alloys tested were straight Lyman #2 and 50/50 Lyman/pure

Lube is a soft mix of floor wax, Vaseline, paraffin, and a little synthetic motor oil. Works for the 158 I'm shooting and bore looks clean.

Twist was measured as best I could with a tight patch and a rotating bearinged cleaning rod. Barrel is 16.25 inches long but not quite 15 inches is threaded because of the chamber. So in roughly 15 inches of travel I get almost a full rotation of the cleaning rod. Is there a better way to measure this on a barrel that is shorter than the actual twist rate?

CJR
03-01-2018, 11:57 AM
Neverhome,

Some preliminary questions for you:

1. What is the sprue hole diameter in your mould?
2. Describe how you cast; i.e. normal temperatures or slightly superheated(degrees above melting), air-cooled or water quenched, etc.
3. What type of casting flux; i.e. Marvellux, sawdust, etc?
4. If this is a NOE mould, what is the location of the CP(Center of Pressure) and the location of the CG(Center of Gravity) ? NOE typically provides this info on their bullet drawings.

After getting these questions answered, if you like, we can discuss bullet stability as researched/patented by the US Air Force and Arrow Tech,VT.

Best regards,

CJR

outdoorfan
03-01-2018, 12:07 PM
For kicks and giggles, I would shoot that bullet real slow (subsonic or maybe even well subsonic) with a fast/faster burning powder to see if it looks somewhat stable at the lower end of the velocity scale. I've gotten a 190 grain wfn in my Rossi 92 357 magnum to shoot 3-4 MOA most of the time with a mere 600 fps. And that is to 100 yards

But, like R5R said, life is too short to continue to mess with it if you've done everything you can to make it work.

bosterr
03-01-2018, 12:08 PM
All of my MGM barrels have the rate of twist etched underneath.

Neverhome
03-01-2018, 12:17 PM
I've tried it numerous times subsonic but I don't know HOW subsonic. Used various amounts of Clays and Trailboss for these plus a safe but lighter load of H110 .I do own a chrono but don't currently have a set up for portable lighting or anything of appropriate height to sit it on at the range. I mean I could put the chrono downrange but that is asking for a shot chrono with this bullet.
Anyway, all attempted velocities failed to reliably hit an 18 inch target at 50 yards.


For kicks and giggles, I would shoot that bullet real slow (subsonic or maybe even well subsonic) with a fast/faster burning powder to see if it looks somewhat stable at the lower end of the velocity scale. I've gotten a 190 grain wfn in my Rossi 92 357 magnum to shoot 3-4 MOA most of the time with a mere 600 fps. And that is to 100 yards

But, like R5R said, life is too short to continue to mess with it if you've done everything you can to make it work.

Neverhome
03-01-2018, 12:23 PM
I'd have to get home to measure the sprue hole. I'll check it later.

I don't check temp of the melt yet but I typically run the pot just at the point where it starts to oxidize as I ladle. Mold is hot enough to fill out. Latest batch was filled out but not frosty. When I run the 158s I have to make them frosty to get fillout but the 225 does ok without.

Flux is usually a good stirring with a paint stir stick. It burns as I go.

yes Noe mold. I'll check the drawings for CP and CG.


Neverhome,

Some preliminary questions for you:

1. What is the sprue hole diameter in your mould?
2. Describe how you cast; i.e. normal temperatures or slightly superheated(degrees above melting), air-cooled or water quenched, etc.
3. What type of casting flux; i.e. Marvellux, sawdust, etc?
4. If this is a NOE mould, what is the location of the CP(Center of Pressure) and the location of the CG(Center of Gravity) ? NOE typically provides this info on their bullet drawings.

After getting these questions answered, if you like, we can discuss bullet stability as researched/patented by the US Air Force and Arrow Tech,VT.

Best regards,

CJR

Neverhome
03-01-2018, 12:27 PM
CG= 46.21% from base

CP= 47.99% from base



Neverhome,

Some preliminary questions for you:

1. What is the sprue hole diameter in your mould?
2. Describe how you cast; i.e. normal temperatures or slightly superheated(degrees above melting), air-cooled or water quenched, etc.
3. What type of casting flux; i.e. Marvellux, sawdust, etc?
4. If this is a NOE mould, what is the location of the CP(Center of Pressure) and the location of the CG(Center of Gravity) ? NOE typically provides this info on their bullet drawings.

After getting these questions answered, if you like, we can discuss bullet stability as researched/patented by the US Air Force and Arrow Tech,VT.

Best regards,

CJR

Neverhome
03-01-2018, 12:28 PM
Mine says 16 twist but I felt like I should check it just in case


All of my MGM barrels have the rate of twist etched underneath.

popper
03-01-2018, 01:53 PM
Marginal stability- go faster, barely stable above 1K fps. Also sounds like they need to be sized smaller - tails on the recovered, concave base. Might try a slower powder.

Neverhome
03-01-2018, 03:35 PM
Well that is interesting input! I had no idea what that might indicate nor that it was out of the ordinary. Thank you



Marginal stability- go faster, barely stable above 1K fps. Also sounds like they need to be sized smaller - tails on the recovered, concave base. Might try a slower powder.

popper
03-02-2018, 12:14 PM
My 40s are 16:1 works well with short but your heavy is much longer. Longer is higher BC but needs faster twist (or fps).

Larry Gibson
03-02-2018, 03:17 PM
Have to disagree with popper. Your .95" long bullet in a 16" twist has an Sg (stability factor) of 2.16 at 1000 fps, an Sg of 1.44 at 300 fps. That is using the Miller formula which gives bullets full stability at an Sg of 1.4. I have shot the RCBS 35-200 which is longer than your bullet down to 500 fps out of 16" twist 35 Rems and 35 Whelens with excellent accuracy. Something else is happening. Can you post a picture of you cast, sized and lubed bullets?

Neverhome
03-02-2018, 04:05 PM
Everything I read and checked said I should be golden stability-wise as you said. It's been my feeling as well that something else is at work here but I couldn't pinpoint it.
I don't have any cast at the moment. Haven't been making any for obvious reasons. I'll cook
Up a handful later.

I had a chance to shoot today briefly in the literally 35 mph winds here on the East Coast. Winds were at 6 o'clock thankfully and I was only shooting at 50. Gun grouped well with 4 different bullets. Lee 125, 158, and 200, and Hornady 158 xtp.
Ive demonstrated plenty often that I can put all the pieces together but I feel like I'm missing something with the 360-225. None of the above bullets are SWC. Is there anything loading-wise that is pecular to SWCs?

Neverhome
03-02-2018, 05:00 PM
As cast

215559

Sized

215560

303Guy
03-02-2018, 06:00 PM
I would suspect internal voids in the casting.

I've discovered voids that were invisible on the casting but once fired, the void collapses under pressure, becoming visible.

Try cutting underweight castings just to see.

https://www.artfulbullet.com/index.php?threads/interesting-gas-cut.1244/

Neverhome
03-02-2018, 06:10 PM
I'll weigh this batch and see how consistent they are!


I would suspect voids in the casting, likely near the base.

I've discovered voids that were invisible on the casting but once fired, the void collapses under pressure, becoming visible.

Try cutting underweight castings just to see.

runfiverun
03-02-2018, 06:45 PM
I would show all that info to your rifle.

Neverhome
03-02-2018, 07:13 PM
You're right. Trial and error is a much better idea than a little FREE research.

Maybe I'll try one of those 300 grain Thumpers NOE makes and just let the rifle tell me if it'll work instead of doing a little research first. No?


I would show all that info to your rifle.

runfiverun
03-02-2018, 08:44 PM
you can research read and calculate all you want.

the only one that has the answer to all your questions is the target.
that's just how it is.

Neverhome
03-02-2018, 09:19 PM
Ever read a reloading manual? 2? 3?

They obviously won't show you how your rounds will print on paper as you say but I hate to break it to you but that's research preliminary to the actual shot.

Ever pose a question on here? Research yet again.

I guarantee you that the AMU researches continuously and then as you say tests on paper. They are constantly looking for an edge and I guarantee they don't just throw random components together.
But I do agree on one thing, your rounds need to group on target or why bother.






you can research read and calculate all you want.

the only one that has the answer to all your questions is the target.
that's just how it is.

Neverhome
03-02-2018, 09:43 PM
Thought about this some more. So I loaded up a couple different velocities with the 225 and fired into duct seal. That's how I recover mine.
12 grains of H110 and 10 grains of IMR 4198.
Nothing special about these loads except one would be high pressure/velocity and the other lower pressure/velocity.
The point was just to recover the bullets and inspect the bases.

Both showed similar slight concaveness and finning where the trailing edges were pulled back by the rifling.
Then I shot a load with a Lee 125 and 5 grains of Clays. This shot fantastically today at the range.
Same exact look to the base when recovered.

The bullet bases LOOKING the same is not very scientific I guess but lets say they are the same.
Could the finning cause a uneven release from the crown? And if so would the short 125 in the 16 twist be affected in the same way as the long 225?


Marginal stability- go faster, barely stable above 1K fps. Also sounds like they need to be sized smaller - tails on the recovered, concave base. Might try a slower powder.

Neverhome
03-09-2018, 01:37 PM
Had a chance to hit the range today. Decided ahead of time to load just a handful of these rounds but enough to test at 25 yards and 50. All previous testing was done at 50. I wanted to see what they'd do going faster, as suggested, but at both distances.

Here is the NOE 360225 launched at about 1250 ft/sec at 25 yards using a 1x red dot.

216085


Here it is at 50. Nothing changed but the distance. Only 2 holes because the third went off paper.

216086


This is screaming unstable to me and really seems to act not unlike a full wadcutter. This swc is virtually straight up and down at the nose. Almost no ogive to speak of.

Could that be what's happening? It's falling apart like a wadcutter at distance?

Neverhome
03-09-2018, 03:03 PM
For the sake of argument, here is the Lee 358-200 at 50 yards with no load development.


216094

popper
03-10-2018, 12:32 PM
Larry is right, I fumbled the Miller. Your 50 yd looks like barely tilted holes but that could be the backer moving.

Neverhome
03-10-2018, 03:23 PM
Larry is right, I fumbled the Miller. Your 50 yd looks like barely tilted holes but that could be the backer moving.


The pictures are terrible...
But up close they definitely show carbon on one sideof the hole on most of the rounds fired.
Wasn't a still day so the target could have been moving but at this point I'm inclined to believe that they are yawing as distance increases.

oldblinddog
03-10-2018, 05:07 PM
Try Unique or Bullseye. I canít recommend a load with that bullet, but a search of the site ought to provide you with a starting point with these two powders.

Try here: http://castboolits.gunloads.com/showthread.php?227609-38-200-load&p=2586400&viewfull=1#post2586400