[Ralph McLaney]

Marshall has apparently added a new mold for the 38/357 BTB 185 FNGC.

According to my measurements:

New: .728" long, and 1.566" oal seated in 1.278" Starline cases.

Old: .728" long, and 1.611" oal seated in 1.278" Starline cases.

The new version should be better suited to lever actions.

Will the new version supersede the older bullet or will there be a choice?

 

[MikeG]

Interesting. I will have to compare to what I have on hand and see which version I have....

 

[Ralph McLaney]

A better picture:

This is a better picture:

 

[Bill M]

Great job Ralph! You are really on top of this. Seating this bullet .050 deeper will change the powder charges that are safe with the bullet. I have loaded some of the "old" style bullets seated down to 1.535" (factory crimped) and it TOTALLY changes the nature of the bullet with H-110. My perspective here is only with 4" revolvers though

Does anybody know when this change went through? I've got a fair supply of these bullets and will have to open them up to make sure which is which.

 

[Ralph McLaney]

Boxes of both in my last shipment.

Bill M.

I don't know when the new 185BTB was added, however, I just found it illustrated on the BTB rifle bullet selection chart under
35 Caliber Rifle 185g FN GC.
Notice however, the bullet specifications shown are incorrectly listed the same as the old 38/.357 185g FN GC.

http://www.beartoothbullets.com/bulletselect/details.php?id=28

The old 185BTB is shown in handgun bullet section:

http://www.beartoothbullets.com/bulletselect/details.php?id=37

I received boxes of both in my last handgun bullet order for the 38/357 185g FN GC. Both bullet types had the same box label.

 

[Ralph McLaney]

View of S&W cylinder with new & old BTB 185 FNGC

Bill M.

I agree with your statement:

"Seating this bullet .050 deeper will change the powder charges that are safe with the bullet. I have loaded some of the 'old' style bullets seated down to 1.535" (factory crimped) and it TOTALLY changes the nature of the bullet with H-110."

However, the new 185BTB also gives the bullet greater "running room" prior to contacting the chamber throat - this may flatten the pressure curve. The new 185BTB measures .353" just ahead of the crimp groove, in comparison the old version measures .358" just ahead of the crimp groove.

This picture shows how far each version of the BTB 185 FNGC bullet will travel when dropped into the cylinder of a S&W 686. Each bullet is sized to .358". The protruding bullet is the new BTB185.

 

[Ralph McLaney]

Load work up.

CAUTION: This post discusses loads or load data that equal or exceed published maximums for the cartridge(s) mentioned. Neither the writer, The Shooter's Forum, nor the staff of The Shooter's Forum assume any liability for damage or injury resulting from using this information. DO NOT ATTEMPT TO DUPLICATE THE DESCRIBED LOADS without first working them up from a published safe starting level charge while watching for pressure signs. If you don't know how to do that, don't try. <!-- / message --><!-- sig -->

Bill M.

These loads were worked up from the first box of Beartooth 185 FNGC bullets I opened. I did not realize this was a different bullet than you and Marshall have written about so many times. This underscores the importance of starting low and working up as well as the value of checking new bullets with a micrometer first!

Using Blue Dot and H-110 powders, I worked up loads based on data contained in the current Speer #14 Loading Manual for 180 grain 357 Magnum Silhouette loads and the load recommendations from you and Marshall.

Temp 48F
Distance to chronograph screens 8 ft.
Six rounds fired with each load.
Firearm: S&W 686 4 inch barrel .357 Magnum

"New" 185gr BTB FNGC, 10.7 grains of Alliant Blue Dot, new Starline brass and Winchester Small Pistol primers:

1301 FPS average, 79 fps extreme spread, Low 1257 FPS, High 1336 FPS.
Minimal primer flattening.

4/6/2010 update: The above listed load showed high pressure signs when later tested in higher temperatures and MUST BE REDUCED.

----------------------------------------------------

"New" 185 BTB FNGC, 15.9 grains of H-110, new Remington brass, and Winchester Small Pistol primers:

1269 FPS average, 71 fps extreme spread, Low 1230 FPS , High 1301 FPS.
Some primer flattening.

------------------------------------------------------

For comparison:

Double Tap 180 Gr. FNGC Factory Ammunition:

1263 FPS average, extreme spread 53 FPS, High 1286 FPS, Low 1233 FPS
Some primer flattening.
--------------------------------------------------------

 

[Bill M]

Hi Ralph,

You are getting some very interesting results there. I find the Blue Dot load to be the most interesting as you are getting 100 fps more than I am. I am shooting a 4" GP-100 with the cylinder throats opened to .359 and the barrel firelapped on top of that. Obviously the GP cylinder is longer too. Not that the GP is any better but that it certainly is different than your 686. I checked and I do not have any of the new "shorter" bullets. My last delievery from BTB was 7/09.

The 10.7gr Blue Dot load in my GP is hardly a max load. Maybe with your seating the new bullet deeper you are getting a good mix of higher pressure with mitigated peaks. Just as guess though but 1,300 fps with this bullet out of a 4" bbl is screaming. It will be interesting if you see a pressure difference with hot weather.

Much like you posted, I got a lot less velocity out of H-110 than what was expected. With the old 185gr bullets I could pour silly amounts of H-110 behind that bullet and barely get over 1,200 fps out of the gun. It was not until I shortened the loa to 1.535" and gave it the strong crimp of the Lee Factory crimp that the H-110 behaved and gave me some outstanding velocities for a 4" bbl. I won't post them here because my GP is a long ways from standard.

Good data Ralph. Keep up the good work.

Bill

 

[Ralph McLaney]

Both are good bullets...

Bill M.

Both are good bullets with characteristics to meet different needs. Marshall needs to clearly list and label these separately to avoid any confusion.

I have already put together work-up loads for the "old" 185 FNGC to try on my next range trip. It will be interesting to see how a stock 4" S&W 686 runs those Blue Dot and H-110 loads over the chronograph.

 

[Ralph McLaney]

More load testing:

CAUTION: This post discusses loads or load data that equal or exceed published maximums for the cartridge(s) mentioned. Neither the writer, The Shooter's Forum, nor the staff of The Shooter's Forum assume any liability for damage or injury resulting from using this information. DO NOT ATTEMPT TO DUPLICATE THE DESCRIBED LOADS without first working them up from a published safe starting level charge while watching for pressure signs. If you don't know how to do that, don't try.
---------------------------------------------------------------------
Bill M.

Today, using Blue Dot and H-110 powders, I worked up loads for the "Old" 185gr FNGC. Again, the loads were based on data contained in the current Speer #14 Loading Manual for 180 grain 357 Magnum Silhouette loads and the load recommendations from you and Marshall.

Temp 65F
Distance to chronograph screens 8 ft.
Six rounds fired with each load.
Firearm: S&W 686 4 inch barrel .357 Magnum
Bullet: 185 grain FNGC .728" long, and 1.611" oal when seated in 1.278" Starline cases.

-------------------------------------------------------------------

"Old" 185gr BTB FNGC, 10.7 grains of Alliant Blue Dot, new Starline brass and Winchester Small Pistol primers:

1248 FPS average, 33 fps extreme spread, Low 1226 FPS, High 1259 FPS.
Minimal primer flattening.

----------------------------------------------------

"Old" 185 BTB FNGC, 16.0 grains of H-110, new Starline brass, and Winchester Small Pistol primers:

1224 FPS average, 46 fps extreme spread, Low 1197 FPS , High 1243 FPS.
Minimal primer flattening.

-------------------------------------------------------------------

Both of these loads exhibited a much lower extreme velocity spread, and a lighter-smoother recoil impulse. This 185 gr. bullet also has a full diameter forward "band" that just touches the start of the cylinder throat.

I have no doubt this rendition of Marshall's load (H-110/W296) would show greater velocity gains in longer barrels, but in a 4" tube this slow burning powder just doesn't have room to build more velocity.

On the other hand the Blue Dot load, suggested by you, was a clear winner in the velocity department and had a suprisingly low ES. With more powder space, this Blue Dot load really smooths out. This BD load impressed me with a substantially lower muzzle blast and recoil than the previous BD load / bullet combination.

 

[Bill M]

Glad to see you are getting such good results Ralph. I have found the Blue Dot load to be a wonderful mix of power and control in a 4" gun.

Those new 185gr bullets should fit your 686 better as they won't be pushing into the cylinder throats.

Have you done any accuracy testing yet?

Bill

 

[Ralph McLaney]

Accuracy testing is next.

Bill,

I have not done any formal accuracy testing as yet.

I don't think 50 fps one way or the other is going to make a major difference in the hunting field, so the most accurate load will ultimately fill the cylinder.


Ralph

 

[Bill M]

Hey Ralph,

I finally went back and dug up my origional notes from the Beartooth .358 185gr gc load from June, 04. With 10.7gr of Blue Dot, 6 shots averaged 1,193 fps with an es of 17 fps. Don't read too much into this though as the numbers can move around a bit with change in lot of powder, temp and the phase of the moon . The 4" GP I developed the load in has it's cylinder throats opened to .359 and is firelapped. It sounds like your cylinder throats are a bit smaller. That is probably why you got more velocity than I did.

I have only tested for accuracy in this one gun and it's brutally accurate out to 200 yards. I am told this it typical for this bullet.

Have fun!

 

[Ralph McLaney]

S&W 686 and Buffalo Bore 180 LFNGC

Bill M.

Yes the cylinder throats on my stock 686-6 are smaller. As best I can measure with a micrometer, the cylinder throats run a consistent .357 inch.

For what it's worth, I fired some Buffalo Bore 180 grain LFNGC factory ammo earlier this year. The chronograph showed some very high velocities and sharp recoil from the same 686 with 4" barrel:

Temp 50F
Buffalo Bore Heavy 357 Mag
180 grain LFNGC OAL 1.542

1450 FPS average, 90 fps extreme spread, Low 1403 FPS, High 1493 FPS.
Primers well flattened. Slight ejection resistance.

The Buffalo Bore website showed this load making 1375 FPS from a 4" 686 Mountain Gun. However, the crimp shown in the website pictures differed from the crimps on my samples. I don't have my camera available right now, so a description will have to suffice. The crimp looks like the case was pressed into the crimp groove with a collet die (Lee Factory Crimp?) and then the brass above the groove was pressed in to the deep seated bullet with a taper crimp. I have no doubt this extreme crimp helped build pressure in this factory ammunition.


Ralph

 

[Ralph McLaney]

185 FNGC Thread Links

http://www.beartoothbullets.com/bulletselect/details.php?id=37

Thread Links on this bullet:

http://shootersforum.com/showthread.htm?t=1526&highlight=185+fngc

http://shootersforum.com/showthread.htm?t=1040&highlight=185+fngc

http://shootersforum.com/showthread.htm?t=61387&highlight=185+BTB

http://shootersforum.com/showthread.htm?t=1479&highlight=185+BTB

http://shootersforum.com/showthread.htm?t=665&highlight=185

http://shootersforum.com/showthread.htm?t=21981&highlight=blue+dot+357

http://www.shootersforum.com/showthread.htm?t=29190&highlight=357

http://shootersforum.com/showthread.htm?t=1378&highlight=185+BTB

http://shootersforum.com/showthread.htm?t=40183

http://shootersforum.com/showthread.htm?t=34308

http://shootersforum.com/showthread.htm?t=19304

 

[Ralph McLaney]

185 BTB in a Rifle

Classic note from Marshal Stanton on the 185 BTB and 16/H-110 performance from an 18" rifle barrel

http://shootersforum.com/showthread.htm?t=12941&highlight=357

 

[Ralph McLaney]

Update:

CAUTION: This post discusses loads or load data that equal or exceed published maximums for the cartridge(s) mentioned. Neither the writer, The Shooter's Forum, nor the staff of The Shooter's Forum assume any liability for damage or injury resulting from using this information. DO NOT ATTEMPT TO DUPLICATE THE DESCRIBED LOADS without first working them up from a published safe starting level charge while watching for pressure signs. If you don't know how to do that, don't try.

There have been some reports of inaccurate chronograph readings at less than 15 feet due to muzzle blast pressure waves. However, I did not see any substantial difference in the velocities recorded at 8' and 15'

Here are some updates and additions clocked 15 feet from the muzzle:

Temp 75F
Distance to chronograph screens 15 ft.

Rossi R357B single shot 22 inch barrel .357 Magnum.

Double Tap 180gr FNGC factory load:
1742 FPS average, 45 ES, Low 1723 FPS, High 1760 FPS.

"Old" 185gr BTB FNGC, 10.7 grains of Alliant Blue Dot, new Starline brass and WSP:
1562 FPS average, 32 fps extreme spread, Low 1542 FPS, High 1575 FPS.


"New" 185gr BTB FNGC, 16.0 grains of H110, new Starline brass and WSP:
1714 FPS average, 14 FPS extreme spread, Low 1706 FPS, High 1720 FPS.

"Old" 185gr BTB FNGC, 16.0 H110, new Starline brass and WSP:
1723 FPS average, 28 FPS extreme spread, Low 1709 FPS, High 1737 FPS.

Ruger New Model Flat Top, 4 5/8" barrel:

"New" 185gr BTB FNGC, 16.0 H110, new Starline brass and WSP.
1326 FPS average, 30 ES, Low 1306, High 1336 FPS.

"Old" 185 BTB FNGC, 16.0 H110, new Starline brass and WSP.
1262 FPS average, 46 ES, Low 1234 FPS, High 1280 FPS.

"Old" 185 BTB FNGC, 10.7 Blue Dot, new Starline brass and WSP.
1291 FPS average, 70 ES, Low 1246 FPS, High 1316 FPS.


S&W 686, 4 inch barrel:

"Old" 185gr BTB FNGC, 16.0 H110, new Starline brass, WSP.
1225 FPS average, 19 ES, Low 1212 FPS, High 1231 FPS.

"New" 185g BTB FNGC, 16.0 H110, new Starline brass, WSP.
1277 FPS average, 57 ES, Low 1256 FPS, High 1313 FPS.

 

[Ralph McLaney]

Temperature sensitive.

"It will be interesting if you see a pressure difference with hot weather."
Bill M.

Bill,

Your observation was right on target. The combination of higher temperature (48F vs 75F) and the .045" greater seating depth of the "New" 185g FN GC resulted in high pressure signs (pierced primers) with your old top end charge of Blue Dot. This clearly points to the importance of developing loads in warmer temps.


With the "Old" BTB .38/.357 185g FN GC
your load of 10.7 grains of Blue Dot continued to perform very well.

Ralph

 

[Ralph McLaney]

180g Speer .357 Silhouette Bullet

The following information is from the Speer Technical Department:

180g Speer .357 Silhouette Bullet

Speer Bullet Part 4229.

The overall length of this bullet is .800"

The distance from the nose of the bullet to the start of the crimping
cannelure is .390" (+/- .010")

----------------------------------------------------------

This is the kind of information that should be in all loading manuals so that seating depth can be readily compared between bullets of similar weight.

 

[Marshall Stanton]

Ralph and Bill,

Excellent observations and great data on the difference between our original 38/357 185g FNGC and the new version. Sorry to have been absent, but time necessitates making bullets rather than being on these boards, as much as I'd like to, my time constraints dictate only a cursory glance at the forums from time to time.

Indeed, as has been so well described and observed, the bullet has been changed in design. The overall on-game performance is identical to the previous version, but as those molds became worn over time, and out of specification, and beyond their servicable life, we weighed some options, and decided to make the changes noted in this thread.

The reasons for this change were several, but the primary driving force was in regard to lever action rifles shooting these bullets in .357 Magnum loadings. The previous design necessitated either modifying the cartridge carrier on a significant number of both Marlin 1894's and Rossi M92's in order for the loaded round to cycle through the action, or to trim back brass in order to shorten the cartridge overall length to function properly through a number of these guns.

The new design positively averts these issues while preserving the hammer-like qualities of this projectile on game. Albeit at a price of having to readjust loading data to accomodate the resulting somewhat reduced availabe case capacity of the cartridge. Our tests have shown however, that with judicious load development, ballistic performance on a par with the original design is possible.

Overall feedback on the bullet in terms of accuracy, terminal performance and ease of load development have been very gratifying. As with any changes to an existing product, some adjustment must be made and for some of us, we simply don't like change. We have actually only changed the design of four of our bullets over the last 19 years, and in each instance, efficiency and utility have been enhanced. I'm sorry for the inconvenience this has caused for some of our loyal and long time customers.

As always, if there are questions regarding loading data and application of our products, PLEASE, give us a call, and we'll be here for support through whatever questions or frustrations you might have.

Thanks again to all, and especially to Ralph and Bill for their excellent contributions on this thread regarding the differences and the loads shared.

God bless,