Sw 629-6 44 magnum reload overpressure?

[Big-bore-bob]

Hello, I'm new to the forum. This is my first post so I'm not sure I'm doing this right, bear with me please, im new to reloading. My question is: what would cause my smith 629-6, 4 inch barrel 44 mag to chronograph velocities higher than reloading manual states. My load is new starline brass, 240gr XTP, cci 350 primer, 23gr h110. My velocities are averaging 1300 fps, with highest fps out of 30 rounds at 1360. There is some flattening of primers, however there is still some rounding on the edges. Cases are mildly sooty with some soot traveling back to the rim. Cases all eject fine, most just fall right out with a light tap on the ejector. My reference materials include hornady, lyman, and nosler manuals. Am I in dangerous territory? Any thoughts greatly appreciated, thanks.

 

[edwardware]

How much higher, and are you within published charge data for you cartridge, powder, bullet class, etc?

Expecting a precise (within 5%) velocity match between your chrony and Acme's manual is a fool's errand. 10% variation wouldn't be astonishing, but is unusual.

 

[jak67429]

although that is a hot load it does not look like it is over max from Hogdon site

Hodgdon H110 0.429" 1.600" Starting 23.0 1,413fps MAX 25,200 CUP 24.0 1,522fps

 

[Zahn]

I just looked your load details up in both Hornady and Hodgdon, and your velocity numbers look right on the money, perhaps a little high but not dangerously so. Hornady says 1300 fps with 23.5 grains H110 and a 7.5 inch barrel, and Hodgdon says 1413 fps with 23.0 grains from an 8.5 inch barrel.

Edit: Welcome to the site!

 

[NorthBorder]

Welcome to the forum Bob. this thread will probably get moved to the handloading forum, but no big deal. You are at the beginning end of the H110 range, so unless you are seating your bullet too deep you are right where you need to be. I seat my bullet on the crimp groove so that puts my COAL right near the suggested COAL of 1.60"

 

[Big-bore-bob]

Welcome to the forum Bob. this thread will probably get moved to the handloading forum, but no big deal. You are at the beginning end of the H110 range, so unless you are seating your bullet too deep you are right where you need to be. I seat my bullet on the crimp groove so that puts my COAL right near the suggested COAL of 1.60"

How much higher, and are you within published charge data for you cartridge, powder, bullet class, etc?

Expecting a precise (within 5%) velocity match between your chrony and Acme's manual is a fool's errand. 10% variation wouldn't be astonishing, but is

Thanks for the reply, I don't have my books in front of me at the moment but my COAL is 1.590-1.60, I did trim my brass to 1.730 instead of 1.750 just so my crimp would be uniform across the batch (had a few short ones). My velocities are about 150fps faster than one of my books. About right on with my hornady book, however they use a 7.5 inch barrel and mine is 4 inch. This prompted my concern.

 

[edwardware]

Thanks for the reply, I don't have my books in front of me at the moment but my COAL is 1.590-1.60, I did trim my brass to 1.730 instead of 1.750 just so my crimp would be uniform across the batch (had a few short ones). My velocities are about 150fps faster than one of my books. About right on with my hornady book, however they use a 7.5 inch barrel and mine is 4 inch. This prompted my concern.

Type your reply outside the quote.

The difference you see could be explained by a snug b/c gap, a tight bore, a miscalibrated chrony, dumb luck, or any combo thereof.

Smile and shoot.

ETA: and, when you chrony a load, at book max, that's 150fps slow, remember this and don't come around whinging. It happens.

 

[243winxb]

My question is: what would cause my smith 629-6, 4 inch barrel 44 mag to chronograph velocities higher than reloading manual states

All lots of powder dont have the same burn rate. From slow to fast, maybe 5% difference. The cylinder/barrel gap may be at .004" the minimum.

Best to stay away from the maximum 24.0 gr load. Pressure spikes possible. If you must increase powder charge, go 3/10 gr at a time.

MY S&W M29-2
Heavy loads of W296 caused peening (arrow) of the metal around the center pin . This caused the pin to stick inward. Fixed by removing pin and opening hole with the correct size drill bit. Installed new center pin.

 

[GeoDudeFlorida]

I just looked your load details up in both Hornady and Hodgdon, and your velocity numbers look right on the money, perhaps a little high but not dangerously so. Hornady says 1300 fps with 23.5 grains H110 and a 7.5 inch barrel, and Hodgdon says 1413 fps with 23.0 grains from an 8.5 inch barrel.

Edit: Welcome to the site!

You beat me to it.
I think what you’re seeing is why people (incorrectly) recommend higher starting loads with H110. At low pressure and low case fill H110 is dirty and erratic. I wouldn’t worry about flattening or rounding on the edges of primers - a wild guess says that indicates low pressure, not high - or the smudge pot cases - ditto, could maybe indicate the cases ballooned slowly and didn’t seal quite before the bullet left the case mouth.

W296/H110 is a great magnum powder but it is touchy to deal with. I really don’t recommend it for beginners because of that but I’m sure millions of handloaders have started with it and never had a problem so take it with a grain of salt.
But do work up a 1/2gr in 12-round batches until you find a good load or hit Hornady’s published max.

 

[Zahn]

You beat me to it.
I think what you’re seeing is why people (incorrectly) recommend higher starting loads with H110. At low pressure and low case fill H110 is dirty and erratic. I wouldn’t worry about flattening or rounding on the edges of primers - a wild guess says that indicates low pressure, not high - or the smudge pot cases - ditto, could maybe indicate the cases ballooned slowly and didn’t seal quite before the bullet left the case mouth.

W296/H110 is a great magnum powder but it is touchy to deal with. I really don’t recommend it for beginners because of that but I’m sure millions of handloaders have started with it and never had a problem so take it with a grain of salt.
But do work up a 1/2gr in 12-round batches until you find a good load or hit Hornady’s published max.

THIS!!!
I loaded some H110 into .357 Magnum, both 158 grain and later 125 grain bullets. I started at minimum on the 158, something I don't generally do. I normally start a little up from the bottom. Then I went up by 0.2 grains. I didn't have a chronometer at the time, but I saw the start of pressure signs.

Minimum loads on the 125 grain bullets produces the most impressive report and flash. Let's just say, I treat H110 with great respect. It is not a forgiving powder.

 

[Big-bore-bob]

Thanks for all the replies everyone, much appreciated! I'll treat the h110 with the respect it deserves. I appreciate and will follow the advice given. Thanks for helping out a newbie!

 

[joneb]

I have seen signs of over pressure in later models of S&W revolvers, I have noticed tighter cylinder throats in S&W compared to Ruger?? I've had good results with 22.8gr of H-110 with 240gr XTP and WLP in Win or Fed and R-P cases for 44 Rem mag. This could be a work down scenario for the Smith.

 

[black mamba]

The bothersome part of your OP for me is the sooting on cases with that high of pressure. Leads me to believe you may need either a heavier crimp or a larger diameter bullet. My near max H110 loads come out pristine clean.

 

[Hookeye]

IIRC I had sooting w WW296.
Just considered it "dirty".
180 and 200 gr max loads, in a couple 629s.

 

[Walkalong]

Type your reply outside the quote.

Fixed it

 

[Big-bore-bob]

The comment about tight chamber throats got me curious so I took an xtp and shoved it through the front of the cylinder holes. It was TIGHT! Took heavy thumb pressure to pop it out the other side. Would the 629 benefit from cylinder throat reaming to fit a wider range of projectiles? The xtp bullets are .430. By the way factory remington 180gr. And wwb 240gr are also sooty.

 

[edwardware]

It was TIGHT! Took heavy thumb pressure to pop it out the other side.

No, tight is good for jacketed. If you could push it through without a hammer, it's not too tight.

If you want to shoot cast bullets, you'll likely need to revisit that to avoid undersizing them into the bore.

 

[Big-bore-bob]

These comments are great food for thought. I have plenty of rounds left from that batch so I can chrono some more and see if I had a fluke with the velocities. My crimp is pretty stout, I'm using a lee factory crimp die to separate seating and crimping. The top of my crimp lands about 2/3 to 3/4 of the way up the cannelure. I just got check weights for my digital scale and I could use work on my powder throwing technique, my extreme spread for those rounds was 102 fps. Standard deviation was low 40's. The best I've done was a SD in the upper 20's and ES of 67 I believe, that was during my ladder test. Only difference was I used remington once fired brass on that lot, same primer, bullet and powder charge. I blasted a single half dollar size hole in the paper at 50ft from the bench (accuracy seems good).

 

[2ndtimer]

One other factor to consider is the cases you are using. I haven’t loaded .44 magnum for years, but note that Hodgdon data uses Winchester cases and you are using Starline cases. I have read that Starline brass in .223 Rem. is heavier than other brands. Not sure if their .44 Mag brass is heavier than Winchester brass, but if it is, the reduced case capacity could also contribute to higher pressure with Starline brass. If Starline brass is thicker, it could also partly explain the mild soot you noted with your loads. If you have other brands of brass, comparing their respective weight on a scale might be informative.

 

[Walkalong]

velocities. My crimp is pretty stout, I'm

Look anything like this?

 

[Hartkopf]

Just curious, how close to the chrono were you shooting?

 

[Big-bore-bob]

The above posted pictures look similar to my crimp, my bullets are seated a smidge deeper and I'm rolled in slightly more I think, looks closer to the round on the right, hard to tell from the picture. My chrono is about 6 feet in front of the muzzle. Possibly unburnt powder throwing off my readings? Move chrono further out to say 10ft?

 

[Slamfire]

The comment about tight chamber throats got me curious so I took an xtp and shoved it through the front of the cylinder holes. It was TIGHT! Took heavy thumb pressure to pop it out the other side. Would the 629 benefit from cylinder throat reaming to fit a wider range of projectiles? The xtp bullets are .430. By the way factory remington 180gr. And wwb 240gr are also sooty.

According the periodicals of the period, this M629 had tight throats, it was deliberate by S&W, and it gave outstanding accuracy.



I had to cut loads to compensate, or I would be beating my ejector rod with a block of wood! It is an acceptable trade off, exceptional accuracy for load reducing.

 

[Big-bore-bob]

This crimp look OK? Too much? I'm not crushing the case or anything. Chambers great, no round is jumping the crimp.

 

[Soonerpesek]

This crimp look OK? Too much? I'm not crushing the case or anything. Chambers great, no round is jumping the crimp.

I'm thinkin' you just answered your own question.................................looks stout, but good...................IMO