Gunsmithing Baffling problem with new barrel

[Falar]

This is not rifle related, but hopefully I can get some good input here from some experienced smiths.

I purchased a 10" .429" 8 groove 1:18" blank and had my gunsmith make an 8" barrel for a Dan Wesson I had just bought. My first time out shooting it, I brought along one of my usual handloads that I run through my other .44s; 18.2gr of N110 underneath 300gr XTPs in Winchester cases. This is a "hot" load, near SAAMI max. Right at 36k PSI according to QL. However, many people routinely load to 40-44k PSI in .44 Magnum (I've used some loads in this range too) so they are well within the "safe zone" IMO. I fired a full cylinder over the chronograph and noted that the velocity was much lower than it should have been. At first I thought the chrono was incorrect because it was shaded, but got a suprise when I tried to open the cylinder. It was seized and I had to slap it open, which was not a good sign. Predictably, I had to hammer the ejector rod to get it to extract the spent cases. The cases showed significant signs of pressure and one even ruptured! Something is causing these loads run at 60k+ PSI in this gun. I am lucky the gun is a robust design and DID NOT explode. I fired some of the exact same ammo through my Desert Eagle just before that and they were just fine, so I know that even though handloads are involved here it is NOT an ammunition problem. I immediately figured the barrel might be the culprit and had it slugged. The lead came out at .422" diameter which seemed ubelievable to me. I called the barrel maker and they were astonished as well and asked me to send it in and if they slugged it and got the same results that they would take care of me. My gunsmith checked the barrel and measured .429" diameter though which doesn't make sense. He also slugged it and got .422" just like me but a .422" drift goes right through. A seriously tight barrel is the only cause I can come up with as to how the chamber pressures could double with the same ammo from one gun to another so that explanation would fit.

Before I send this barrel in and make an ass out of myself, does ANYONE have ANY idea what the hell is going on here?

 

[338RUM runner]

Re: Baffling problem with new barrel

My guess is the threads at each end. One or both are not right.They are making the end small and thats why when you slug it you get .422. DW was fun to get to shoot right, when you got it right they worked great. Have shoot IHMSA for 30 years. Good luck.

 

[Falar]

Re: Baffling problem with new barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: xp100man</div><div class="ubbcode-body">My guess is the threads at each end. One or both are not right.They are making the end small and thats why when you slug it you get .422. DW was fun to get to shoot right, when you got it right they worked great. Have shoot IHMSA for 30 years. Good luck. </div></div>


Since I had a 10" blank and needed an 8" barrel I have 2" of unturned raw barrel stock that was parted off and we slugged it and got .422" as well.

 

[longshooter]

Re: Baffling problem with new barrel

0.422", is this bore, or groove?

 

[Falar]

Re: Baffling problem with new barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: longshooter</div><div class="ubbcode-body">0.422", is this bore, or groove? </div></div>

I measure the slug at the widest points, so I'm assuming it is the grooves.

 

[longshooter]

Re: Baffling problem with new barrel

If the groove is 0.422", how does your 0.422" drift get past the rifling?

 

[Falar]

Re: Baffling problem with new barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: longshooter</div><div class="ubbcode-body">If the groove is 0.422", how does your 0.422" drift get past the rifling? </div></div>

I am wondering the same thing.

 

[longshooter]

Re: Baffling problem with new barrel

Measure your cylinder throat diameter. Or, will a XTP bullet drop freely through each chamber in the cylinder?

 

[Falar]

Re: Baffling problem with new barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: longshooter</div><div class="ubbcode-body">Measure your cylinder throat diameter. Or, will a XTP bullet drop freely through each chamber in the cylinder? </div></div>

They do pass through. I have to work until 6 today but will do some more testing this evening with factory ammo, the original barrel, and the same reloads and try to rule a few things out.

 

[phideaux]

Re: Baffling problem with new barrel

I have been almost exactly where you are. I had a .44 mag desert eagle and ran some pretty warm loads of 2400 powder and a 310 hard cast bullet through it a lot. the eagle worked fine. use those same loads in a Ruger Redhawk and they worked fine. then tried the Dan Wesson .44 mag in stainless with factory barrel. those loads hammered the dog shit out of the Dan Wesson.
very sticky cases, hard to open cylinder but no flattened primers or headstamps, but within about 40 rouns, the Dan Wesson cylinder would spin in either direction cocked or not. the cylinder hand and bolt were toast. i replaced those parts and got rid of the Dan Wesson. your barrel does seem really suspect if your cylinder throat checks ok. i'd sure let the barrel maker see it.

 

[Falar]

Re: Baffling problem with new barrel

The barrel has been ruled out. I fired some factory loads and they were fine. I fired some HOT handloads using some 260 and 275gr cast bullets and they were fine. It is something about the 300gr XTP that causes the problems. I will try the 240gr XTP and see if it does it as well. The throats are kind of small compared to some other revolvers we've checked but it is still strange that only the one particular bullet causes a problem (so far).

I guess I have to call up Pac-Nor and eat some crow now.

 

[longshooter]

Re: Baffling problem with new barrel

You're overloaded, according to the Speer reloading manual #12. Wesson's have tight throats, and call for a couple grains less powder, max. You need to start with starting loads that are less than that 2 grains less powder. You might need to open the throats if you wish to use those 300s. Are you seated in the bottom cannelure?

 

[Falar]

Re: Baffling problem with new barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: longshooter</div><div class="ubbcode-body">You're overloaded, according to the Speer reloading manual #12. Wesson's have tight throats, and call for a couple grains less powder, max. You need to start with starting loads that are less than that 2 grains less powder. You might need to open the throats if you wish to use those 300s. Are you seated in the bottom cannelure? </div></div>

Yes, bottom cannelure 1.74" COAL and max according to Vihtavuori is 20.2gr. I tried loads throughout the whole min/max range in the VV manual and QL puts these loads well under max. It HAS to be a combination of the 300gr XTP and the tight throats because 275gr HC bullets with loads in excess of published maximums did NOT produce the same results.

 

[longshooter]

Re: Baffling problem with new barrel

You are listing a cartridge oal that is above the listed max.

According to the Speer manual, Wesson's require some special considerations that need to be understood. If it's your first Wesson, you might want to get these things in your mind. I have a premium revolver that I had to send back for them to "bust out the bottom". That is, the throats were too tight for the load, and as far as I was concerned, too tight for the larger forcing cone, also. They opened the throats.

Anyway, they fixed it. And I was happy. But when you have a problem, you do have to get to the bottom of it.

If I were you, I'd start getting some measurements, and recording them for future usage. Check bullet diameter, throat diameter, check for bullet to chamber interference, things like that.

And for sure, stay away from full house loads.

 

[longshooter]

Re: Baffling problem with new barrel

From the Speer Manual number 12:

"When loading for Colt and Wesson Arms revolvers,seat the bullet in the front cannelure,and use 300 grain data in the 44 Magnum RIFLE section of this manual. Be sure to begin with starting loads."

That rifle section calls for lesser powder. Starting loads get to be about ~ 5 grains less powder than you are currently using. You should check out the SPEER. They don't have your powder, but they do give a representable idea about your Wesson.

I hope that Speer does not mind me using a portion of their manual.

 

[Falar]

Re: Baffling problem with new barrel

I know this is old now, but figured I'd post anyway.

The issue was barrel gap. Standard is .006" for pretty much any swing-out cylinder revolver but I had been taking advice from other wheelgun shooters than .002" is "better" and had my cylinders at .002"-003". It really made that much difference in pressure!