Marlin 357

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Re: Marlin 357

Postby mtngun » Fri Feb 15, 2008 5:31 pm

When I slugged the barrel on my 450 Marlin, I used an egg fishing sinker instead of a slug. In case your not familiar with them, they're football shaped with a hole through the length. I have tried soft slugs and round balls, but found the egg sinkers were more user friendly. Only the middle of the sinker is in contact with the bore so between the tapered ends and the thru hole you don't get any obturation from your ramrod. I also applied a light coat of WD-40 to the clean bore and sinker before slugging.

I went from the muzzle end and had to tap the sinker through the first two inches. My barrel is the 18.5" ported version. I was able to hand pus it to the magazine dovetail, then had to tap it for another half inch. From their it hand pushed to the stamped letters. Only light tapping was required to get it through the lettering and out.

I've always cleaned the barrel with J-B and Kroil oil on a very tight patched jag. After getting it pretty clean, I can just feel the tight spots when finishing up. It has improved greatly through use though.

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Re: Marlin 357

Postby mtngun » Fri Feb 15, 2008 5:39 pm

Trying a 190 gr. in 1894 357

Since a 180 gr. hasn't done anything to crow about in this rifle, I thought a heavier bullet would be worth trying. It's not that I want or need more weight, but sometimes a longer bearing length helps accuracy.
Image

I walked the powder charge up to see how much velocity I could get away with. Each powder charge was weighed, and all loads used a Federal #200 primer, Felix lube, and heat treated mystery alloy sized to 0.359".
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It looks like 15.4 gr. Lil Gun will deliver 1725 fps at sane pressures. That's about what I expected, and in fact, I brought along 15 rounds loaded with 15.3 gr. for accuracy testing. Three 5-shot groups at 100 yards averaged 3.87", using a 2.5X scope. However, velocities and pressures were much lower than expected.
Image

The powder for the 15.3 gr. load was thrown directly into the cases without weighing each charge, so it's possible the setting was a little off.

In any event, accuracy was still ho-hum. Next time I'll load another 15 rounds and be sure to get the powder charge right, and repeat the accuracy tests.

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Re: Marlin 357

Postby mtngun » Fri Feb 15, 2008 7:14 pm

OK, last time there appeared to be a error in the powder charge, so I loaded the 190 grainers with 15.4 and 15.6 gr. of Lil Gun and gave it another chance to show us what it's got.

Since last time, the 2.5X Leopold has been replaced by a Williams 5D. The front sight is still in limbo while I experiment with different ramps and blades to get the elevation right, so for today the front sight assembly was attached to the barrel with only masking tape. It worked better than it sounds.

When the scope was mounted, I would run the pressure trace cable back along the top of the barrel, but today I ran the cable under the barrel, to avoid interfering with the line of sight.

Also since last time, I hand lapped the barrel for the third time, because there was some suspicion that the first two inches on the breech end were still a little tighter than the rest of the barrel. I was never sure whether the tight spot was for real, but I figured that if the tight spot was real, lapping would help, and if the tight spot was not real, lapping would not hurt.

Also today's loads were assembled with a lighter than normal crimp. Let's say it was just enough crimp to turn the case mouth inward, but not a heavy crimp like I would use on a wheelgun.

Sorry to bore you with all these details, but it's leading up to something.

I shot three 5-shot groups with 15.4 gr. Lil Gun and three 5-shot groups with 15.6 gr. -- 100 yards, Fed #200 primers, felix lube, 0.359" heat treated mystery alloy, 190 gr.

it may be a few months before the new forum software can digest the following table
[table]
[mrow] [col] 15.4 Lil Gun [col] 15.6 Lil Gun
[row] Avg. Velocity [col:] 1719 [col] 1737
[row] std. dev [col] 1.1% [col] 1.1%
[row] Avg 5 shot group @ 100 yds. [col]4.4" [col:] 3.3"
[/table]

The best group of the day was 1.9" with the 15.6 gr. charge. Now if it would just do that every time .......... :lol:

Here's a PT for the 15.4 gr. load, showing only the nicer looking traces.
Image

Here's some of the funny looking traces for 15.4 gr.
Image

Here's the first two strings for the 15.6 gr. load, with only the bogus traces deleted (this particular strain gage installation is very noisy and always produces a few bogus traces that have to be deleted).
Image

Now here's the last four shots for the 15.6 gr. load. This is the string that shot the nice 1.9" group -- is it a coincidence that this string also has the most consistent traces?
Image

So what the &*!@# is causing the second primary peak? I dunno, especially since this particular setup has always had a lot of electrical noise and always produced a few bogus traces. However, today's 2nd primary peak happened enough times that it cannot be immediately dismissed as electrical noise.

So what have I learned? Well, about 15.5 gr. Lil Gun is max for this 190 gr. bullet, and it should produce about 1725 fps.

The effect of light crimp vs. heavy crimp definitely needs to be explored.

I'm not totally sold on Lil Gun. It gives significant secondary spikes that could be hurting accuracy. Lil Gun gives nice velocities, and I've got an 8 pound keg of Lil Gun that I don't have any other use for, but I have more confidence in tried and true WW296.

Next time I'll do the crimp experiment with 15.5 gr. Lil Gun, and I'll also try 296 with the 190 cast.

Another thought is to try trimming 357 Maxi cases to about 1.32", which should chamber in this gun's goofy "toilet bowl" throat. That would put the case mouth right up against the beginning of the rifling, so the bullet would not have to leap across a 0.380" diameter throat like it does now. I'd have to cut a mold with a nose designed for the longer cases, but I think it's worth a try.

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Re: Marlin 357

Postby mtngun » Fri Feb 15, 2008 7:16 pm

I think I would use that keg of Lil Gun for a stool while your filling your cases with WW 296. I've only tried Lil Gun in my 480 Ruger SRH. Can't say I liked it. While accuracy was good, the pressure spiked real fast. Just a 0.2 gr increase went from no pressure to a fully flattened primer. With WW 296 you could watch the primer gradually flatten. You knew what to expect with the next powder increase. Lil Gun gave me no early warning.

Your lever gun's accuracy is not too bad, that's what I get with my 686 with a red dot. At 100 yards. :lol: :lol:

I recently tried a CPB 180 WFNGC in my 686 with 12.0 grs WW 296, CCI 550, and heavy crimp. Clocked at 1,150 fps, with 1 1/4" 50 yd groups.

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Re: Marlin 357

Postby mtngun » Fri Feb 15, 2008 7:46 pm

Another trip to the range to play with the 190 gr. cast and 15.5 gr. Lil Gun, however, stuff happened.

As mentioned before, the barrel had been hand lapped. I hand lapped instead of firelapped to avoid eroding the throat. Nonetheless, the bullet nose now barely touches the rifling when a cartridge is chambering, whereas before lapping, the nose engraved quite securely.

A new front sight and ramp were taped to the barrel with masking tape. The masking tape worked pretty well last time, but today it wouldn't stay put, and finally parted company alltogether (this load kicks a bit), so accuracy testing was out of the question. Today's sight experiment did confirm that the sight height is near optimal, so I'll go ahead and screw it on. BTW, the combined height of the ramp and sight is 0.350". Normally a taller sight is required with peep sights, but maybe this gun isn't normal. :roll:

The strain gage on this gun has always been electrically noisy, and it has been common to get one or two bogus traces on every string. That was annoying, but I could live with it. It has worsened over time so that now the bogus traces outnumber the good traces, and I no longer have confidence in the pressure data. I'll give up on this strain gage and mount a gage on top of the barrel. It'll be ugly, but I'll take it off if and when I finish tinkering with loads.

One test was with Maxi cases turned down to 1.330", to help fill in the oversize throat. Actually, it only filled in about 1/3 of the freebore, because the other 2/3 is too small for the case mouth. A different bullet was required with a shorter nose and shorter front band. Accuracy averaged 5", but the uncooperative taped-on front sight made the results meaningless.

Another test was with no crimp vs. a very heavy crimp. By this time I had given up the front sight and could only hope to collect pressure and velocity data, but the traces were hopelessly noisy. For what it is worth, the no-crimp velocity averaged 1729 fps vs. 1737 with the heavy crimp. The no-crimp standard deviation was 1.00% vs. 0.84% with the heavy crimp. Based on the velocity data, it appears that the crimp may be helping a tiny bit, but it's not a big deal. I'll go back to using a moderate crimp.

Another test was with WW296 powder. QL suggested a max charge of 16.1 gr. for about 1725 fps. Actual velocity averaged 1748 fps with 0.66% standard deviation. Four traces looked believeable and the rest looked suspicious.
Image
Image

The only conclusion I can draw about 296 is that the 0.66% standard deviation is better than what is normally seen with Lil Gun.

I'll get the sight permanently attached, install a new strain gage, and then try again.

If I could figure out how to modify the lifter timing to feed a 0.425" long nose, then QL says 296 would push a 200 gr. bullet to 1720 fps. That would be pretty impressive, and a 200 gr. bullet might improve accuracy. The longer nose would make it feasible to recut the leade to a gentler angle, too (a shorter nose would not be able to reach the rifling if the leade were recut).

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Re: Marlin 357

Postby mtngun » Fri Feb 15, 2008 7:58 pm

I mentioned on another thread that the iron sights on my Marlin 1894 357 were crooked. I had to replace the front ramp with a lower ramp, anyway, so a new screw hole had to be drilled. The picture illustrates how far off the original sights were. The barrel had been screwed in a little too much.

Image

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Re: Marlin 357

Postby mtngun » Sat Feb 16, 2008 8:15 pm

Update on the 190 gr. bullet

I recut it with a slightly fatter nose, so that it engraves snugly when chambered. It didn't seem to help accuracy, though. Here's how it does at 100 yards, with peep sights.

average of 6 strings (standard aperture) -- 4.75"

average of 3 strings (another day) -- 5.50"

average of 5 strings (ghost ring) -- 5.3"


Except for the occasional lucky group, it's stuck at 5 MOA with the peep sight. A scope could probably tighten groups a little, but I don't like putting a scope on this gun. I've tried different diameters, different lubes, and one different powder, and it doesn't seem to make much difference. I haven't tried a smaller meplat, or lower velocity, or different alloy, or jacketed bullets, but I don't want to go there. I'm out of ideas, and hunting season is drawing near, so I'll probably just stick with this load. It'll be fine out to 100 yards.

The load is 15.4 gr. Lil Gun and a Fed #200 primer. Velocity is 1737 fps with Rooster HVR lube. A softer lube will drop velocity 10 - 20 fps, but doesn\'t seem to affect accuracy.

By the way, the POI changed when switching from an aperature to the ghost ring (aperture removed from the Williams 5D). That wasn\'t supposed to happen, but it did. I sighted it in for the ghost ring and will stick with it from now on.

The good news is that I really like the gun and I shoot it quite well from field positions. It just seems to point naturally and hang steady. It\'s easy to understand why these rifles are so popular. Today I took turns shooting a scoped, MOA, bull barrel 22 LR and the Marlin 1894 at swinging targets, from a standing position, and was getting more hits with the Marlin than with the 22.

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Re: Marlin 357

Postby mtngun » Sat Feb 16, 2008 8:17 pm

Question: Kind of a sinful question, but have you tried this rifle with a decent jacketed bullet. Say a 158 gr Hornady XTP, 16-17 grs of WW296, and a magnum primer. You may just have a bad gun period. Most Marlin levers are good shooters.

Reply: No. It would probably do much better with a jacketed bullet, but I bought the gun to shoot with cast bullets. A lot of my customers load for lever actions, so I wanted to learn more about them. Plus I have always had a soft spot for lightweight, easy-to-carry guns.

Actually, you don't hear of very many Marlin 357s shooting well with cast bullets, especially at full throttle, and especially at 100 yards. For a long time it was blamed on microgroove rifling, but now they have switched to deep cut rifling and yet the story remains the same. If you ask me, the throat has been the real problem all along. The throat problem in rifles chambered for handgun cartridges was written up in the American Rifleman 20 years ago, by Ed Harris, if I remember correctly, yet the factories still turn out dysfunctional throats.

If I ever get bored with life, I'd like to set the barrel back an inch and recut the chamber with a proper throat. It would be enlightening to see how much difference the throat makes, on the same barrel.

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Re: Marlin 357

Postby mtngun » Sat Feb 16, 2008 8:46 pm

With great reluctance, I tried a 75% meplat on the 190 gr. bullet. The bore riding section was also shortened a bit to improve the aerodynamics. The 80% meplat has never tumbled or made oval holes in paper, but sometimes when a blunt bullet is marginally stable, it just won't group well.

At 100 yards, the 75% meplat averaged 4.15" for four 5-shot strings. All 20 shots spanned 7.00". That's with the ghost ring sight. The 4.15" average may or may not be a statistically significant improvement over the 5" groups turned in by the 80 percenter, but I was impressed that every group had three or four shots in a decent cluster, something that rarely happened with the 80% meplat. For now, I think the 75% meplat gets the nod.

Perhaps an even smaller meplat would improve accuracy further, but I don't want to go there. You can argue that a few thousanths difference in the meplat will not make a noticeable difference on game, but you can also argue that benchrest accuracy will not make a noticeable difference in the field. My take is that the 357 needs as much meplat as possible while still providing decent field accuracy. I've shot deer and a black bear with a small meplat 357 (the Lee SWC) and wasn't impressed with the tissue damage -- basically, there wasn't any tissue damage.

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Re: Marlin 357

Postby mtngun » Sun Feb 17, 2008 5:01 pm

It's been a while since I posted pressure data for the Marlin 1894 357.

I removed the original strain gage, which had always been electrically noisy and seemed to be getting worse as time went by.

I installed a new gage using loctite 4211. It redlined on every shot. Turned out the glue had stuck to the barrel but the gage didn't stick to the glue very well.

Yet another gage was installed with loctite 4211. It worked OK for a few shots and then it, too, began redlining on every shot. Once again, the glue stuck to the barrel but the gage peeled away from the glue quite easily.

At this point I gave up on loctite 4211. It was not recommended by RSI. I experimented with it on my own initiative because I like its two minute set-up time, but it appears that it does not have a good affinity for the gage's plastic substrate.

A third gage was installed using the loctite 401 supplied by RSI. When I got to the range, the cable would not snap into the gage's female connector. Turns out some loctite had seeped into the connector. Geeezzz :evil:

OK, so then a new connector was soldered on and finally everything seemed to work beautifully. Here are the first four shots with the new gage. This is my 160 gr. PB wheelgun load, 1948 fps out of the Marlin. These traces include a +5000 psi calibration offset as explained later.
Image

But then here is the rest of that string. It looks suspicious to me.
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At this point, I put some more tape on the connection and rerouted the coil of cable away from the muzzle. Now here it is with the 190 gr. rifle load. Two suspicious traces have been deleted.
Image
This gage is located near the case mouth. It's supposed to be over the center of the case, but that would put it too close to the receiver, so it is a compromised location, and it may not give true absolute pressures. It still can be useful for comparing one load to another.

Quickload thinks the revolver load needs 37.7 ksi to get 1942 fps out of the rifle barrel. QL is far from perfect, but it usually gets the velocity/pressure relationship right even if it errs on the powder charge. That was my rational for adjusting the gage calibration to make the revolver load show about 37 ksi.

If you believe my gage calibration, the 190 gr. load is also a little warm at about 36 ksi. SAAMI spec is 35 ksi. I can live with 36 ksi in the rifle load, but I may back off the revolver load a little bit.

If I have time, I'll load a few jacketed bullets for calibration purposes. There is lots of pressure tested data available for jacketed bullets. I don't like to use cast bullets to calibrate a gage because cast bullets have more variables.

Notice that today's traces do not have secondary spikes, aside from the occasional suspicious trace. The original gage showed modest secondary spikes with most loads.


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