Sunday, October 21, 2007

Shot a military rifle match today!


This afternoon I escorted the Grand Old Turk to a military rifle match.

I score 408 out of 500...... a personal best for me.
That put me in the top five or six out of twenty shooters, with the best overall score being right around 438 I think. That put me about 30 points off top score.

The targets shone are slow fire prone (no sling) on the left, and slow fire off hand (no sling) on the right.

Photo Sharing and Video Hosting at Photobucket

My scores are usually in the 270/285 range, with my previous best score around 310. What did I do different this time? Very little. I stuck a bit of non-skid tape on the slip on recoil pad so the rifle would stop dancing on my shoulder, and also did the previously mentioned work on the firing pin protrusion.

In fact, my sitting position rapid fire stage performance was poor, but at least all shots scored. Another happy little fact.... this was the first match I ever fired where every single shot was scorable!

Todays match was open to 'any military', and most of the shooters were using AR platform rifles. A few garands, and two other shooters were firing Mausers as I was. What makes my score particularly sweet to me was the crowd I finished with. To a man they were all shooting $1000+ match AR rifles with match loads, while I was shooting a $100 Turk Mauser with about $50 worth of work and my own hand loads.

Enough crowing on my part...... It was fun and they are a great bunch of shooters to spend time with. It sure does make the match go nicer when the holes in the target are in the right places (g).

(The video is NOT me, but a friend who also shot the match that day.
He was shooting a very sweet 1935 Columbian Mauser in fine condition.)


Saturday, October 13, 2007

Firing pin protrusion on a 1938 Turkish Mauser

I have two 1938 Turkish Mausers. Having typical 1898 Mauser actions, these are robust and simple. The same techniques used by generations of shooters on Mausers work just fine on these old Turks.

One Turk is set up as my ‘military rifle shoot’ competition piece (known and feared on rifle ranges everywhere as ‘The Grand Old Turk’). I also have about 2500 rounds of 1950’s 8x57mm ammunition. The idea being to use the surplus for practice, and my quality hand loads for competition.

Sounds like a plan, doesn’t it?

There is a fly in the ice cream with this plan…. my Turks won’t shoot the Yugo ammunition reliably. I get what appear to be good firing pin strikes, but every other round fails to fire. The same ammo, even the FTF rounds, will all shoot with 100% reliability in my Yugoslavian M48B (another version of the 98 Mauser).

Clearly the ammo is good, and there’s an issue with the Turk’s that I needed to find.

My first thought, and a good one, was firing pin spring strength. The M48 is about fifty years old, while the Turks are much, much older. Springs weaken with age and the Turks are noted for it. New 24 pound springs were ordered, received, and installed. Immediate range tests revealed no change at all in function. The Yugo ammo still had about a 50/50 failure rate in the Turks.

Careful side-by-side inspection of the M48B bolt vs. the Turk bolt showed the problem to be one of firing pin protrusion. The M48B was 0.058” while the Turks were 0.030”. Since the spec for firing pin protrusion on a model 98 is .055" to .065", No matter how hard the pin struck on that Turk it simple wasn’t hitting deep enough to set off the stubborn and hard Yugoslavian primers.

Mauser 98 actions do not offer ready firing pin protrusion adjustment like a Mosin does. It’s built into the engineering, and pretty much soldier proof. That left me with a problem and no easy solution. New firing pins cost roughly what I paid for the rifles to start with, and were not guaranteed to solve the issue. I needed a tinker fix.

I determined the limiting factor on firing pin protrusion to be the striker stopping against the bolt shroud. Modifying that requires disassembling the bolt and some careful dressing with small files. This work is touchy and must be taken slowly. Too much metal removed means a trashed part and a trip to the Internet for new components.

It might also mean pierced primers and a dangerous rifle.

If you chose to follow in my footsteps, be careful. If minor gunsmith work is something you fear, leave this job to the pros.

As I write this, I still have to range test my work. I have confidence it will all perform as planned, but I expect to be spending a bit more time removing a touch more metal before I am fully finished. At this point I have extended the firing pin protrusion on one of my Mausers from .030” to 0.040”. While still minimal, it may be all I need to do.

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Follow up adventures in Mauser bolt workings:

Using the procedure detailed above, I continued a step at a time till I arrived
at 0.055” protrusion on the firing pin. This should be acceptable with a Model 98 Mauser action, which calls for 0.055” to 0.065”.

The results are thus: From a 50% fail to fire with 1950’s Yugoslavian surplus, the rifle now has a 10% fail to fire. While not perfect, it’s far better than it was. Since the firing pin protrusion now stands at only 0.003” different between the M48 and the Turk, any more fail to fire with the Yugo surplus ammunition is probably caused by another factor. (I suspect the shape of the firing pin tip….)

More to the point, the old Mauser shoots it’s favorite hand load considerably better.
Fliers are a thing of the past. I have since shot a military rifle match that entailed a fifty-eight round course of fire. Eight sighter rounds, with fifty for score. In that entire match I did not have a single flier. On top of that, my score came up substantially from previous matches with little else changed but what is detailed above.

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

Sunday, October 7, 2007

Slugging a bore, the easy way!

Photo Sharing and Video Hosting at Photobucket

One of the interesting features of military surplus rifles are the unique bores each has. It’s entirely possible to have one Enfield with a bore measuring at .312” in the grooves while the next of the same model measures at .315”. Both are quite usable and probably capable of surprising accuracy. A handloader seeking the best accuracy needs some data regarding the rifle, and chief on the list is the actual diameter of the bore.

The accepted method of learning true bore diameter involves ‘slugging’ the barrel. Boiled down, the process involves pushing a soft lead slug through the bore with some type of rod. With any luck, and a moderate bit of skill, what’s gained is an exact sample of the rifles grooves and lands impressed on the lead, ready for easy external measurement.

I must admit the thought of pounding anything through the bore of one of my precious mil-surp rifles leaves me shaken. For some reason the violence of firing one doesn’t bother me at all, yet slowly pounding a misshapen lead slug down the bore is met with fear and trepidation.

While reading an article on loading double 0 buck in the 8x57mm as a backyard load, the author mentioned the easy procedure of simply pushing the lead ball into a case with thumb pressure. Hmm….. that didn’t seem too hard! I had a new-to-me Yugo M-48a mauser in 8x57mm, and suddenly also had a burning desire to know the actual dimensions of it’s pristine bore.

A quick trip to the work shop found some Sellior and Bellot 12 gauge 00 buckshot shells ready to be sacrificed. A slice of the crimp allowed a small palm full of soft leads balls to roll out onto the loading bench.

Photo Sharing and Video Hosting at Photobucket

Using a digital micrometer to check the balls, they appear to have been formed by random pounding with large rocks. The ‘round’ slugs were actually misshapen and varied in dimension by over .010” from round. That aside, the most important measurement had the slimmest diameter still at .327”, while the stated groove on my Mauser is .323”. That left plenty of lead to give a sample while still being quite easy to push through the barrel. Sampling several left me with two mostly round balls of buckshot just right.

Photo Sharing and Video Hosting at Photobucket

I intended to use two slugs to check my own technique, and be assured of making a stable measurement.

As with any firearms work, the first step is always to make the weapon safe. In this case I removed the bolt as I wished to push my ‘slug’ from the breach to the muzzle. Knowing the rifle would be muzzle down , the barrel was padded with
multiple layers of clean folded paper towels. This also served as a soft bed for the test slug to land on without being damaged. There is some force involved with pushing the lead ball through the bore. It’s best to take no chance and prepare ahead.

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

While steadying the rifle against my leg, the lead ball was dropped into the chamber. It came to rest in the throat of the barrel, ready to begin it’s long bore journey. Next, a heavy cleaning patch was placed against the chamber as padding for the rod and a way to center the rod in the bore.

Photo Sharing and Video Hosting at Photobucket

The rod is now pushed into the chamber till the folded patch stops against the lead ball. Force is slowly applied against the ball, with perhaps a light strike on the cleaning rod handle to get it started into the bore. Once the buckshot is slid into the bore it should get much easier to push. In fact, it can usually be slid right through the bore with very little pressure at all.

Photo Sharing and Video Hosting at Photobucket

Care should be taken to not force the slug into the padding at the muzzle. The lead is soft and will deform enough to give a false measurement. As long as the slug is pushing freely, it’s best to lift the rifle a few inches and allow the lead ball to fall free onto the padding.

Once the ball has suffered it’s long slide and landed on the paper towel, remove the rod and patch and check the bore. It should be clean and clear of obstruction. In the case of my Mauser the bore looked polished after slugging.

Photo Sharing and Video Hosting at Photobucket

The product of our labor should be A simple round ball with a clear and reasonably precise imprint of the lands and grooves from the bore. Now we have something we can measure! The measuring tools consist of an outside micrometer for the groove diameter and a vernior caliper for the land diameter. The caliper can be used for both, but the micrometer will typically give a more accurate measurement and the groove diameter is the one regarded as necessary for accurate projectile choice.

Photo Sharing and Video Hosting at Photobucket

The slug is carefully closed between the anvils of the micrometer. It’s best to use the ‘clutch’ on the mic if it has one. This will allow a more consistent reading and avoid compressing the soft lead sample. Care must be taken to measure the flattest part of the groove, not the edge of the lands (seen in reverse as indents in the lead sample). In the case of my mauser we can see the actual groove diameter is 0.3235”, or just .0005” over nominal. For all intents the rifle appears unfired.

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

To measure the lands (or indents in the sample slug) we must switch to the caliper. This tool has measuring jaws that narrow to near knife edge and should easily reach the depth of the indent where the micrometer cannot go. Again, care must be taken to not force the tool into the lead. A light touch is called for. There should be just enough friction of the tool on the lead to prevent the ball falling free of the jaws. No more should be needed.

Photo Sharing and Video Hosting at Photobucket

Photo Sharing and Video Hosting at Photobucket

The lands of the mauser measured at .313”. Again, nominal for this rifle. While the rifle appears unfired and the bore is pristine, knowing the actual dimensions will allow choosing the exact best projectile for accurate shooting. Brought together with careful loading technique this rifle will have every chance of being an outstanding and accurate rifle.

Technorati Tags:

Powered by ScribeFire.