Ruger M77 UM (update on current results)

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Sig685

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Long time since I've been here.

I thought I would let you have a peek at my latest build, I call it a Ruger M77 UM for Ultra Match. This is the rifle I have put together for F-TR competition at long range, 800/900/1000 yards. It is my Ruger M77V circa 1983, with some modifications.



The caliber is 308 Match. The stainless steel barrel is a Broughton 5C in 1:11 twist and 32.25 inches long 7.9B contour. The stock is a Boyds and the scope is a Nikon Monarch 6.5-20X44 AO. The rings are Burris Signatures on top of Burris adapters for Ruger M77. The trigger is a Timney set to about .5 pounds and the floor plate and trigger guard are all steel.

I have just broken in the barrel today and it liked load #2 very much. It put all five shots in a tight little group right around a half inch in diameter at 100 yards. Ot course, it was doing this two feet above the point of aim.

I have to load up some more of load #2 and at the next 1000 yard match, we will see if the calculated come up works out.

The whole thing weighs about 17 pounds (barrel is 9 pounds by itself) with the bipod mounted and it is 52 inches long. It is a competition rifle; I would not want to walk around with it unless it was in its own powered cart.
 

Sig685

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Thanks. Its first match is set for 3 weeks from tomorrow. 1000 yards. I'm hoping it does well.
 

Sig685

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I discovered the primers were cratering so I decided to get the firing pin hole fitted with a bushing.

I've always liked the M77, but it required quite a bit of work to transform into a real shooter. I look forward to its first 1000 yard match.
 

Sig685

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Well, after the firing pin hole has had a bushing installed, I find that my velocity for the heavier bullets is higher than a 30-06 by quite a bit and close to the velocities of a .300 Wind Mag with a 24 inch barrel. The additional 8 inches of barrel really make a difference, more than I expected.
 

mattsbox99

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Very cool, I'm planning on a 6.5 Creedmoor in the KM77VT when they come out in June. I've been doing a lot of research on that cartridge and it seems that its got the .308 crowd on the scare.
 

IndianaBoy

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I have noticed firing pin cratering in my M77VT 220 Swift, with a load that is a full grain under the listed max load.

The edges of the primers retain their radius, not flattened at all, so I don't believe I am pushing the pressure envelope.

Are there any safety issues to consider if I am within safe pressures?
 

Sig685

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mattsbox99":2ddujaaf said:
Very cool, I'm planning on a 6.5 Creedmoor in the KM77VT when they come out in June. I've been doing a lot of research on that cartridge and it seems that its got the .308 crowd on the scare.

The 6.5 Creedmoor is indeed a very interesting cartridge. If I was building a non-F-T/R rifle, it would be very high on my list. But my heart is all in F-T/R right now and there are only two calibers for that discipline: .223 and .308. I will be using my Match AR-15 in .223 for the MR course and the Ruger M77 UM in .308 for the LR portion.

I look forward to a report on your experiences with the 6.5 Creedmoor and I wish you a lot of success with it.
 

Sig685

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IndianaBoy":31eq8v5t said:
I have noticed firing pin cratering in my M77VT 220 Swift, with a load that is a full grain under the listed max load.

The edges of the primers retain their radius, not flattened at all, so I don't believe I am pushing the pressure envelope.

Are there any safety issues to consider if I am within safe pressures?

Well, not really a safety issue as long as the primer doesn't burst. I find that the firing pin hole on the Ruger bolt is larger than it has to be and that allows the primer to flow into the hole at ignition time. I consider the M77 to be a very strong rifle and I like to drive mine a little hot (ok, a lot hot,) so in order to safely do that I elected to get a bushing put in. This shrank the firing pin hole quite a bit and the primers no longer crater. If you want to drive yours a little warmer, you may want to consider getting that done. It cost me $50 and took a few days. I'm sure you can find a gunsmith in your area to do that; look for a gunsmith that works on match guns.
 

IndianaBoy

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Thank you for the information.

I don't intend to exceed any published loads, but it is nice to know that the symptoms I was seeing were a result of an excessively large firing pin hole, and not because I was nearing dangerous pressures. That is the diagnosis I had reached based on several reloading manuals, but it is nice to have it confirmed.


None of the primers were pierced, and the load shot extremely well, so I will probably stick with it.

It was only a 3 shot group, but it was under an inch at 200 yards.
 

Sig685

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The .220 Swift is a nice cartridge but it is overbore, which mean the throath will erode quickly over time, do be aware of that. I have shot against folks using .220 Swifts at 300 yards and they can be VERY accurate. The only thing that gets then is when the wind starts bolwing. Because of the usual 1:14 twist in the .220 Swift rifles, the longer high-BC bullets are not able to be shot in these rifles, so the long range accuracy suffers when the wind blows.

On the other hand, there is an excellent selection of highly accurate short flat-base bullets that do a tremendous job in the .220 under 300 yards. I am very happy for you that you have a very accurate rifle with a load to match; take good care of it.
 

IndianaBoy

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If I am ever lucky enough to wear out the barrel on this swift I plan to rebarrel it with a fast twist barrel in the same caliber.

:)
 

mattsbox99

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There is a bit of a trade off though, with higher speed you can get away with a slower twist, try a few heavier bullets and see. You won't be able to get away with the 80s, but you might find a moly coated 75 that shoots well in your gun.

The only rifle competition around here is NRA HP, which I shoot with an M1 Garand. I shoot USPSA 3 gun events with a 11.5" barreled AR15.

Could you explain F-T/R a little more?
 

Sig685

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Yes, you can overcome a slow twist with a higher velocity, after all what you are looking for is a spin rate. The spin rate of a bullet is a function of twist and muzzle velocity; increase either one and the spin will increase. However it should be noted that the required spin rate for a bullet is a function of the inherent instability of the bullet and the muzzle velocity. In other words the minimum required spin rate needed to stabilize a bullet will increase as the bullet is made more unstable or its velocity increases. The air resistance is what creates the need for spin and the higher the muzzle velocity, the greater the air resistance and thus the greater the tendency for the bullet swap ends and tumble at so the higher the minimum required spin.

All this to say, that as you go faster, you need more spin on the bullet. So you can make up a slower twist with a higher MV, but only by a small increment.

F-class shooting is very much like NRA HP, except for a couple of things; 1 the targets are similar but smaller and 2- the competitor is allowed to use optics and support for the rifle. In fact a lot of places that have NRA HP matches also have F-class matches running concurrently; the course of fire is the same. F-class originated in Canada when an old Fullbore shooter (NRA HP) wanted to continue shooting in competition but could no longer see the target well enough and could not hold the rifle hard enough to compete. This Mr. Farquharson (hence F-class in his honor,) managed to convince the DCRA (Canadian NRA) to allow him and others to compete with scoped rifles and bipods or rests. That form of competition caught on very quickly.

F-class is divided into two sub-classes but both use the same target. This target was sanctioned by the NRA in 2006 and started being used in January of 2007. I’ll come back to it in a minute.
One of the sub-classes is F-Open. This can be compared to prone benchrest shooting, to some extent. The rifles are any caliber up to .33 caliber, they can weigh up to 25 pounds (I think), any sighting system can be used (most people opt for high magnification scopes,) and the rifle can rest on a mechanical device as long as it is not a return to zero gadget. A rear rest is allowed but must not be attached to the front rest. The rifle must be fired from the shoulder.
F-T/R is much more stringent in its rules. The calibers are limited to two: unmodified .223 and .308, any bullet you want. The rifle total weight is 18.18 pounds including anything that is attached to the rifle, such as a scope, sling or bipod. The front rest is limited to bipod or a bag. You can use a rear rest but that is not included in the weight and must not be attached to the rifle.

The course of fire is the same as NRA HP and I will just describe it here quickly for the folks who have never seen it.
The way a match works is that we divide the group of shooters into relays and you need a minimum of 2 relays. I have participated in state matches where we had up to 4 relays, which makes for a long day. If the competition is for HP and F-class shooters, we will have the HP shooters on one series of targets and the F-class shooters on the other, because the targets are different and we do not put new targets for every relay, targets cost money.

So, let's just have two relays. At the start of the match, relay 2 will go to the pits and relay 1 will shoot. The course of fire is usually 2 sighters followed by 20 rounds for record in 30 minutes, at 1000 yards prone slow fire. So, let's say I'm on relay 1. I will guage the wind, set my come-ups on the riflescope and then take my first shot. If I did everything correctly, my target puller will see the bullet hit the berm and pull the target down and find the bullet hole. If I did it correctly and actually hit the target, the puller will put a spotting disk in the bullet hole and a scoring disk in a position that corresponds to my score, in other words, the ring in which the bullet hit the target. The closer to the X-ring, the higher the value; the maximum value is 10. Once this is done the target goes back up. I see where I hit, note the score, make a correction and take the next shot. The target puller sees the shot, brings down the target, moves the spotting disk to the new bullet hole, puts a paster of the appropriate color and the prior bullet hole, moves the scoring disk to the proper position and sends the target back up.

This goes on for the 22 shots, the first two being sighters; they do not count but they help you guage the conditions. For 20 shots, the maximum score is 200 (20 x 10). There are usually 3 matches in a competition. Once relay 1 has finished shooting or time runs out, we swap positions. Relay 1 will go to the pits and relay 2 will shoot.

You are familiar with the SR1 (300 yards), MR63 (500/600 yards) and LR1 (800/900/1000 yards) targets. F-class targets are based on these targets, but have different centers and ring values. Let’s look at the Long Range targets and how we use them in matches that have HP and F shooters.

A brand new target will have the LR1 layout which means that it is white (or rather tan), with a black aiming center. This aiming black measures 44 inches in diameter and there are concentric rings inside the black as well as outside the black.

At the start of every match (or rather at the end of a competition so it's ready for the next competition) we resurface the target or actually just paste a new center on the target. We have two centers that we use; the LR-1 and the LRFC. The LR-1 is the standard long range target used in Palma, HighPower and Service Rifle matches. The LRFC has an X-ring in the middle of the black that is 5 inches in diameter. The next ring is the 10 ring at 10 inches in diameter, the next one is the 9-ring at 20 inches in diameter, the next one is the 8-ring at 30 inches in diameter and finally the next one is the 7-ring at 44 inches in diameter. That is also the total aiming black. There is one more ring in the white and that is the 6-ring which measures 60 inches in diameter. Outside the 6-ring, anywhere else on the target is considered the 5 area. This means that if you hit the target at 1000 yards, the minimum you will get is a 5.

The F-class rings have half the diameter of the HP rings for the same value. This means each ring is one quarter the area of the HP ring. At 300 yards, the X-ring is 1.47 inch in diameter and the 10-ring is 2.83 inches.

Let’s talk about score. I know you are familiar with that but I am explaining it for others who may not know. When you reach a certain level of scoring, you obtain a classification from the NRA. This means that you have to shoot a number of NRA-certified or registered matches and the scores have to be turned in to the NRA. If your scores are below 92%, you are classified as a Marksman. When you get to 92% and above for 120 rounds, (or two complete matches,) you get reclassified as a Sharpshooter. At 94.5% or above, you become an Expert. At 97% or above you are a Master and at 98.5% or above you are a High Master.

I am a Sharpshooter at LR F-class, I broke the 92% threshold but I have not yet attained the 94.55% Expert threshold. We only shoot 1000 yards at my club, so I do not have the benefit of shooting the same target as I described above at 800 and 900. The only time that I have done that, my scores were higher, but not quite enough for Expert. It's very difficult with a .223 in an AR-15, which is why I am going to my Ruger M77 UM in .308. There are no LR high masters in F-T/R and I think there may be a couple of Masters.
 

Sig685

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Last weekend, I finally had the chance to take the M77 UM to the 1000 yard line for the first time since the original post. In the interim, I shot a few rounds through it at 100 yards and it was working very well. I chronoed my LR loads and I was gratified to see they were VERY fast; that long barrel is working out just fine. Velocity AND accuracy are key in this sport. If your bullet can't get there, all the accuracy in the world won't help you and conversely if you can't be accurate, all the velocity in the world just makes you miss at higher speed.

The match went fine, the load and rifle did great; the shooter and the scope did less well but that’s fixable. I truly enjoyed shooting this old/new rascal and it does recoil more than my heavy match AR-15, but not nearly as much as one would expect with such a stout load as I am using in this rifle; the very heavy and long barrel absorbs a great deal of the recoil, gotta hand it to Sir Isaac.

So I thought I would post some pictures of the rifle in full competition trim.

The first picture here shows the rifle on top of the bipod. You can see the rear bag that I use in competition. If you look closely under and just in front of the scope knobs, you can see the B-Square level that I added to the rifle. The three black dots on the barrel are small Velcro dots that hold the mirage shield. The handle underneath the rifle and behind the bipod is the cant adjustment on the bipod.



The second picture shows the rifle from a different angle and here you can see the objects that I mentioned earlier. You can also see the ample cheek piece of the Boyd's stock. I may need to add something in leather to that. We shall see.



The third picture shows the barrel to good effect. You can see how heavy it is and also, how long it is. This is F-class material; I would not want to take this rifle hunting or plinking. It's very heavy, close to 18 pounds in full trim, with scope and bipod.



Here we have a picture of the rifle with the mirage shield installed.



One final view
 

Big Bubba

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IndianaBoy, not to steal the thread, but keep a close watch on the neck thickness on the .220 case. In the one I owned, the necks thickened very quickly due to brass flow with hot loads. This happened at a very fast rate.

Sig685, beautiful rifle! It really makes for joy when you get a rifle that has a "fast" barrel when you chrongraph it! :)
 

Sig685

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Well, the fast barrel is because of two things; the length of the thing (32+inches) and the tightness of the bore. Thanks for the kind words.

I have a new scope coming for it in two days, a Weaver T-36, silver finish. I think it will look nice on it.
 

Big Bubba

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Sig685, I hope you and the new rifle make expert in the near future. Man I sure did like the looks of that tricked AR in pictures! I see the wind flags are moving too.
 

Sig685

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Thanks for the kind wishes. I am so busy these days, I barely get to the matches anymore, but I will make an effort.

Yes, the flags show a full value wind, right to left at about 6-7MPH; hold in the left edge of the 8-ring at 3 o'clock, maybe3:15 o'clock due to the right-hand twist of the barrel.
 
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