GP100 Plan B

[Lefty SRH]

Need some insight, suggestions, opinions....etc. A friend of mine wanted me to come up with a HOT HEAVY .357 magnum load for his 6" GP100 in .357. I told him I have just the boolit and load and My GP100 really shoots it well.

I sit down to day and start loading for his GP. I get the 1st 6 rounds done and try a chamber check them, 2 of the 6 don't go all the way. GREAT, whats this....
I checked the throats because I using a Cast Performance 187gr FNGC (I don't have a heavy .357 mold yet) and the some of the .358 diameter is north of the crimp groove and is bumping the leading edge of the throat. And thats the problem! His throats are slightly undersized, .357".

I chose this boolit for him because he's going into bear country later this year and wants some handgun protection. All they plan on hunting with is a traditional bow.

I need a plan "B" for this gun. I doubt he will want to have the cylinder honed out to .358". Is there a heavy J-word bullet on the market that still penetrates DEEP like a hard cast?

Suggestions?

[fecmech]

How about this?? http://www.sierrabullets.com/index.cfm?section=bullets&page=bc&stock_num=8370&bullettype=1

[dmize]

I wont even go into the reasons for NOT taking a 357 for bear backup. Im sure many others will tho.
How much undersized are the offending chambers? Is it close enough they can be honed out with emery cloth and a slotted rod?

[Lefty SRH]

I had to tap a Hornady XTP bullet thru the throats, to me it needs to be sent back to Ruger. I feel like the throats being this small the barrel will have some leading issues.

[RobS]

Regarding the cylinder throats and leading issues well you won't know until you slug the barrel. The only options you have is to size it to the diameter of the cylinder throats or load it with jacketed.

[dmize]

If there is enough time before bow season see about sending it back to Ruger or removing the cylinder and sending it to Cylindersmith.

[Lefty SRH]

Cylinder smith only does .45s now. Wonder whats going on with him.

[Piedmont]

Size the bullets smaller so they will chamber.

[Love Life]

358429

[RobS]

There is also the idea of getting a boolit design that doesn't have as wide of a front drive band. This would enable the round to chamber however after the boolit makes way through the cylinder throats it would still not tell you whether or not leading would take place due to boolit fit. I've had great results in the 45 cal class with a 453460 design wich has virtually no front drive band.

[429421Cowboy]

Could you size down the front nose band only down to your crimp to eleminate this problem? I feel like that's a bit too much to live with and would send it back to Ruger. There is also the option of opening the throats yourself with sandpaper and split dowel as many suggest here, is there not? Would firelapping help? Sorry just throwing out everything off the top of my head.

[dubber123]

If it's not much short of chambering, just shorten his brass slightly. To shoot my 450 gr. WFN's from my brothers Marlin guide gun, we did just that. worked just fine.

[TXGunNut]

Open up the cylinders....to .454. Better swap out the barrel while you're at it.

[RobS]

Open up the cylinders....to .454. Better swap out the barrel while you're at it.

A complete overhaul!!!:-D

[TXGunNut]

GP100 is a damn fine revolver but all kidding aside I think there are better tools for this job.

[429421Cowboy]

Uh oh, granny get your gun, we may get to see another caliber war! Love the bear gun threads[smilie=b:

[Lefty SRH]

GP100 is a damn fine revolver but all kidding aside I think there are better tools for this job.

This GP100 is the only "TOOL" he has available. I offered up one of my .44's to him but he insisted he takes his GP. So then I offered to load some ammo for him, he accepted that since he knows nothing about proper ammo for this task.
Thats where we stand. This thread wasn't meant for another bear caliber debate.

[44man]

I don't think Ruger will open the throats.
They will measure and tell you they are in specs.
The groove size must be measured first anyway, the throats might be fine as is. In that case, if groove is smaller, size the boolits.
It is really easy to lap throats with a slotted rod and fine emery cloth. Do one at a time until the boolit can be slid through with thumb pressure.
I don't like "flap" lapping. I wrap the emery very tight and make it fit very tight in the throat. Spin slow.

[scattershot]

Can you seat the bullet deep enough to crimp over the front band? Be aware that this will raise pressure somewhat, and you may need to reduce the charge slightly to compensate.

[subsonic]

Just size them down until they fit and forget about it. If he shoots it at the bear enough to lead it up, leading will be the least of his worries. Leading will not affect the accuracy at "bear defense" distances.

[dmize]

If he shoots it at the bear enough to lead it up, leading will be the least of his worries.

LOL!!!!! The EXACT same thing had crossed my mind!!

[Lefty SRH]

Just size them down until they fit and forget about it. If he shoots it at the bear enough to lead it up, leading will be the least of his worries. Leading will not affect the accuracy at "bear defense" distances.

You are right, leading would be the least of his worries next to bear encounter. BUT he has also expressed interest in hangun hunting on the land he owns and therefore Id rather see him with a gun and right size throats. I'm trying to look out for himbest interest in the long run.

[dmize]

Well since this is also a long term thing too,Id clean the barrel up squeaky clean,size the bullets to chamber in all holes and shoot it and see what happens.
Since he will probably be using close to the same load for any serious hunting,finding some way to have the cylinder reamed is about your only remaining option

[Lefty SRH]

I just spoke with him and he doesn't want the cylinder reamed/honed out. If money was no object I'd pay for it myself. But I can't do that. I guess I'll get a .357 sizing die size them down. I got the 1st 6 rounds to chamber but the cylinder doesn't turn freely. I brought gage pins home from work and man they are a VERY tight .357" throat.
Oh well I tried, now for plan C and maybe D.....

[dmize]

Hmmmmm your buddy sounds like some of mine,dont fix it just make it work.

[TCLouis]

I think to solve current probems, I would explain that I could not come up with anything.

To solve future problems I would suggest to him where he can search for factory loads that meet his requirements.

I sounds to me like all the problems as he sits it up are yours to solve, and he holds himself blameless all the way around!

[paul h]

Have the cylinder honed 0.3585", it needs to be done to shoot cast to its potential.

Phil Schaumacher a top brown bear guide says his daughter has carried a 357 mag with 180 gr hardcast loads. I'd venture to say he has more experience with up close and personal bear experiences than the collective experience of the entire forum. And while he's carried a 458 win mag and 505 gibbs, he says the 30-06 is fully capable of the task.

Rember, no matter what you pack, you have to place your shot. A 357 with a heavy hardcast in the brain will stop a bear faster than a 500 S&W in the paw.

[jameslovesjammie]

I'd suggest he buy the ammo. If the cylinders are tight his options are really limited to shooting jacketed ammo.

http://www.doubletapammo.com/php/catalog/product_info.php?cPath=21_27&products_id=337

or

http://www.doubletapammo.com/php/catalog/product_info.php?cPath=21_27&products_id=336

[fecmech]

Someone mentioned 358429 back in the beginning and with HTWW they are about 172-174 grs not far off your original 180 target. Front drive band on most of those are .355 so that's no problem. The 358429 is a very good penetrator in solid form so if it must be cast, take a look at that one.

[Lefty SRH]

Someone mentioned 358429 back in the beginning and with HTWW they are about 172-174 grs not far off your original 180 target. Front drive band on most of those are .355 so that's no problem. The 358429 is a very good penetrator in solid form so if it must be cast, take a look at that one.

HTWW=Heat Treated Wheel Weights?

I think I am going to find (already have) a .357 sizing die and try to size down these CP WFN boolit I already bought for him. See how that works first.

[fecmech]

HTWW=Heat Treated Wheel Weights?
Yes, that or just plain water dropped.

[RobS]

HTWW=Heat Treated Wheel Weights?

I think I am going to find (already have) a .357 sizing die and try to size down these CP WFN boolit I already bought for him. See how that works first.

Sounds like the cheapest route. If leading sets in due to barrel groove diameter and cylinder throat mismatch (if there is this issue) I suppose the next path to travel down would be jacketed bullets.

Hope it works out for you.

[2shot]

Factory ammo

Federal Cast-Core 180 grain .357 Mag.

[Lefty SRH]

Sounds like the cheapest route. If leading sets in due to barrel groove diameter and cylinder throat mismatch (if there is this issue) I suppose the next path to travel down would be jacketed bullets.

Hope it works out for you.

HA! Hope it works out for him! LOL

[RobS]

HA! Hope it works out for him! LOL

:bigsmyl2: Yes for him! And for you too because it's always fun to make a firearm shoot lead instead of J's.............or at least is is for me, then again I'm a cheap S.O.B.

:lovebooli:castmine::guntootsmiley:

[Lefty SRH]

Yep, me too....