Good to Bad—Right Now…

[BCB]

I’m shooting an MGM barrel on an Encore. Accuracy is quite good…

All of a sudden, the accuracy is gone, gone, gone…

I thoroughly clean the bore with J&B, a good solvent, and a good brush. Back to my range, fire a couple of foulers, and accuracy returns…

I have never had a barrel that was so sudden in accuracy change when it is getting dirty…

Anyone else experience such a change? I’m hoping that will end as I continue to shoot and clean. The barrel actually has over 300 rounds through it…

With the instructions from MGM, it indicates, the barrel will tell you when it is time to clean—sure seems that way!!!...

Good-luck…BCB

[Hickory]

Did you break in the barrel?
If not, this 'problem' may go away in time.

[Yodogsandman]

Check the scope and mounts.

[BCB]

Did you break in the barrel?
If not, this 'problem' may go away in time.

Yep. MGM instructions are pretty basic. Shoot a couple then clean, shoot a few more, then clean. Fire a group of so, then clean. That is paraphrasing the instructions, but they don't seem to be so "radical" on cleaning procedures, at least not like some procedures I have seen...

Good-luck...BCB

[BCB]

Check the scope and mounts.

Can't see how scope and mounts could be involved if accuracy returns after a thorough cleaning...

Good-luck...BCB

[BCB]

I'm not knocking the MGM barrel. I am just sort of amazed at how quickly the accuracy goes away and then returns after cleaning. I have never had a barrel that was so abrupt...

Good-luck...BCB

[jsizemore]

Each barrel has it's own rules and it appears you are paying attention. 300 rounds is well past the break in point and whatever it "does" isn't going to get any better. I've got a rifle that holds the x-ring for 18 shots and then throws a 10 and then a 9. Not good enough for match shooting but still a good gun.

[Larry Gibson]

A little more information on the cartridge, load and how many rounds to get "dirty" it took might be helpful.

Larry Gibson

[Randy C]

When you clean the scope it might set back to zero, then shoot it a few time and its way off again, been there, mine would shoot in the yard, but when I drove with it in the pickup it would go south. I hope your problem can be fixed this easy. It took me weeks to figure out the problem, I refused to think it was the scope.

[BCB]

A little more information on the cartridge, load and how many rounds to get "dirty" it took might be helpful.

Larry Gibson

It is the 30-40 Krag, an NOE 311-202-RN, and 27.0 grains of Benchmark. Velocity is 1753 fps...

I am not sure as to how many rounds until it needs cleaned. I am going to try to count them during this session. I'm thinking 40 or less, but that might not be too accurate as I never counted rounds down range in my life!!!...

Still a dang good shooter, but would be embarrassing if it "went inaccurate" if I had guests at my range!!!...

Good-luck...BCB

[MT Gianni]

It may be that a change of alloy or lube will get you further down the road to longer intervals. The joys of shooting cast.

[MostlyLeverGuns]

I too would suspect the scope. Sometimes it just does not seem like it should be. Shoots OK then it does not. Scope problems can be pretty ghosty. I have mostly Leupold VX2's and VX3's and Burris. If the occasional unexplained flyer occurs or a group opens with a reliable rifle and load, I change scopes just because chasing scope problems is annoying and expensive in time, ammunition and irritation. I have some Simmons, Bushnell, Nikon and Tasco too. I don't really trust any of them when a good rifle stops shooting.

[BCB]

This 'scope stuff is interesting, but how do we explain the rifle returning back to accuracy by cleaning the bore?...

How would that make the 'scope work any differently?...

BCB

[gwpercle]

Just try another scope you know is working properly. I had an accurate rifle that started acting like it was possessed by evil spirits ! Would shoot nice groups then patterns and back to nice groups.
I tried every trick in the book but in the end the scope had something inside that was loose. It would stay in position then decide to move around....the patterns , then get back in place for a while...I thought I was loosing my mind.
Just try another known scope to eliminate that possibility.
Gary

[JohnH]

I've had scopes act squirrelly but only cheap ones. I broke a scope once and it went from holding for sub 1" groups at 50 yards to not holding 2"-3". It never came back. I'm curious what kind of rifling the MGM barrel has, is it cut or button rifled or forged. Each method is going to leave a different form of tooling mark(s) that will affect how the lands/grooves collect the gunk which causes accuracy to deteriorate. I have an Encore 25-06 barrel that shot the RCBS 257120 like a house afire with most any reasonable load you cared to use. I then double charged a case with 2400. The gun and barrel held but the barrel now won't hold ten shots on a baseball at 50 yards. The barrel was flaky with jacketed. Go figure. Another barrel I had was an Encore 375 JDJ. That barrel at best sot fair with cast, even though it would shoot like a house afire with jacketed. I traded it against a 243 barrel that has the same problem. Shoots jacketed fine. takes a 3 1/2" circle at 75 yards to catch everything. Boolit is the RCBS 24490 and the bore rider of the boolit won't enter the muzzle And there is no "major group" with some flyers. The group is a random pattern. I've a 280 Remington barrel I can tell a similar story about. I've come to believe the success I had with the 25-06 was a fluke. I've not had these kinds of inconsistencies with bolt guns. I don't mean to paint a bleak picture, just that with the exception of one barrel I've not had an easy journey so far getting a barrel to shoot cast well with my Encore. In fact I'd pretty much describe it as a love hate relationship.

[OS OK]

Is this a new barrel?

[Love Life]

Accuracy drop off is one of the main reasons I keep log books for my rifles. Some rifles I can shoot for several hundred rds without cleaning, some I need to clean every 20 rds to keep adequate accuracy for the game at hand. The rifle tells me what it wants, and I give it to it.

[BCB]

Actually, I do have another ‘scope that will arrive this week. I presently have a Fullfield 4.5x14 on it now, but it is an old one. I ordered the same ‘scope, but it has a larger objective lens and it has a better light-gathering setup. The old Burris has been good and it was good when it was removed from whatever rifle it was on. Yet, I continue to have my doubts it is the ‘scope. It just doesn’t seem to correlate that the ‘scope is bad and becomes O.K. when I clean the bore…

I had an accuracy problem with a 308 barrel that came with this Encore. That is why I went to the custom MGM barrel thinking the longer neck would hold the boolit better—this does seem to be true as accuracy is quite good—but changes for the worse as we know…

I have read, in this thread also, that the Encore may not be a good format for cast. This may be true as the 308 shot jacketed bullets fairly well…

I do have several Contenders with the same action as the Encores—i.e. single shot. Two Super 14’s, a 30-30 Winchester and a 7-30 Waters both shoot cast very well. I also have a 6.8mm SPC with a 23” barrel that shoots also very well. So it is obvious the single shot will shoot cast…

I will try the new ‘scope as I had it order for this particular barrel…

Accuracy is good for this barrel, but the “going crazy” at times and then cleaning to solve this “going crazy” is quite annoying…

Oh well, it is what it is…

Thanks…BCB

[Larry Gibson]

This 'scope stuff is interesting, but how do we explain the rifle returning back to accuracy by cleaning the bore?...

How would that make the 'scope work any differently?...

BCB

You are correct in your assumption; the scope has nothing to do with the problem. Mt Gianni is correct with the lube and possibly the alloy being the problem. The barrel gets fouled and accuracy deteriorates......clean the bore the accuracy returns..........

First thing is to change the lube. You didn't mention the lube you are using but it's usually the problem. If that doesn't cure the problem then look at the alloy. If there is not sufficient tin balanced to the amount of antimony you may be getting "antimony wash". However a good lube will prevent that. Still it's best to have sufficient tin in the alloy.

Last, while benchmark is an excellent powder some powders, especially ball powders with their deterrents that control the burn rate, do not burn efficiently at lower cast bullet pressures. The result many times is heavier fouling that builds to a point of being detrimental to accuracy after so many rounds. I've not worked extensively with Benchmark so I don't know for sure but a simple change to a proven powder in that burning range such as H4895 would answer that question. The use of a Dacron filler may also improve the benchmarks burning efficiency if that is the problem.

Larry Gibson

[BCB]

I am using stick Alox—Lyman to be specific. I do have Carnauba Red available, but I believe with all of my sizing of various cast boolits, I still prefer the Alox, either stick or liquid…

I am using Wheel Weights that I have read are at around .5% tin. I add enough pewter (95% tin) to make the alloy approximately 1.25% to 1.5% tin. I don’t do “severely” accurate weighing, but probably close enough…

The NOE 311-202-RN are casting beautifully and are within a grain or so in weight…

QL indicates with 27 grains of Benchmark, approximately 94% of it is burned…

I assume the antimony wash will appear on the rifling/bore at the end of the barrel? Or at least that would be where I could see it without bore ‘scopes etc. I will look closer the next time I see accuracy deteriorating…

As a note of today, I went to my range that is where I have a trail camera and several gardens. So, I am there almost daily. It was quite windy today so I only fired 3 rounds at 50 yards as that area is fairly well guarded from the wind. I put 3 into almost the same hole at that distance. Measuring the outsides of the holes that were the farthest apart and then subtracting 0.308” I got a group size of 0.21”. This type of accuracy doesn’t occur all the time, but groups are always less than 0.4” at 50 yards. The P.O.I. was right where it was before the inaccuracy excursion occurred a few days before. The barrel was thoroughly cleaned about 6 rounds before the 3-shot group today. So, cleaning definitely makes the accuracy come back…

When this barrel is shooting well, it is capable of hitting 16-ounce beer cans at 200 yards. That type of accuracy is very acceptable to me for what I do with this rifle. I believe this barrel has the potential to be a very good cast boolit shooter…

Thanks…BCB

[Larry Gibson]

Given your lube and alloy I would really suspect the powder is fouling the barrel. Add a dacron filler on top of your load. If that doesn't work try H4895 with a dacron filler.

Larry Gibson

[BCB]

I am always confused on this Dacron filler…

I understand it is to fit loosely in the case not be tamped down on the powder…

How does one get it into the case without pushing it to the powder in the bottom of the case?...

Should the Dacron fill then entire interior of the case?...

Thanks…BCB

[Oklahoma Rebel]

my first thought was a dirty powder, then I would try your carnauba red, and maybe up your tin to 2-2.5%, how much antimony is in there? and change things one at a time, so you will know what helps and what hurts. but since you have a scope already coming, try that first.after I started shooting cast, I almost never clean my barrels, and they don't lose accuracy, I must have got lucky on the lube,alloy,powder combo. best of luck to you! keep us updated-Travis

[BCB]

I just used QL to predict a charge of H-4895 that would produce the same 1753 fps as the 27.0 grains of Benchmark…

It shows 28.3 gains of H-4895 so that might be worth a try. I have not seen that light of a charge listed in any manual. Although I didn’t find a charge of 27.0 grains of Benchmark either—used QL to get that data…

What is interesting is that when I had QL find powders in burn rates a bit faster and a bit slower than Benchmark, it listed a charge of 27.2 grains of Benchmark to produce 1753 fps. I am using 27.0…

Moving Forward…BCB

[OS OK]

I am always confused on this Dacron filler…

I understand it is to fit loosely in the case not be tamped down on the powder…

How does one get it into the case without pushing it to the powder in the bottom of the case?...

Should the Dacron fill then entire interior of the case?...

Thanks…BCB

In an 87% powder filled 8mm, I use .5 grain of dacron to fill to where the base of the boolit is the last part of the stuffing...pushing the last of it onto the powder. I use a little pencil length 1/4" wooden dowel.
Once you have weighed out what you need to fill your case...pull it apart and separate the dacron as much as possible. You aren't trying to pack the powder in the rear of the case by volume and density...it's more like a cloud of dacron taking up that extra space.

You certainly don't want to use grits or malt-o-meal or some such...it could compact in the neck, jam up, and cause a plug for an instant and cause a pressure spike.

[BCB]

Well, got another 70 sized and lubed with stick Alox…

I put a piece of painters blue tape on the stock of the rifle and am doing the count thing to see when the accuracy might begin to lessen…

I thoroughly cleaned the bore to the point that white patches being pushed through came out almost as white as they entered the bore…

So far I have only fired 15 rounds and the rifling at the crown are as clean, almost, as they were after the cleaning. The lube star on the barrel surrounding the crown/muzzle is about as perfect as I can see with a low powered magnifying glass…

Guess we will see how long it takes for accuracy to lessen. If it is 50 or so rounds, I will accept that and hope that further shooting might allow for that number to increase…

This MGM barrel is good as when it is cleaned the bore and grooves look sharp and as smooth as silk. I realize the eye might not pick up all marks in the barrel, but if I compare it to other barrels I observe, it is “perfect”…

We shall see what we shall see as I continue to put lead downrange…

Thanks…BCB

[BCB]

Almost embarrassed to post this pic!!!...

This is the worst I have seen the muzzle on this rifle…

Accuracy has gone downhill again after 35-40 shots…

Plenty of grey-wash on the rifling/bore, but, is that enough or more than enough to cause radical accuracy changes?...

I suppose I could try Carnauba, but I would need to clean my LAM 2 out as stick Alox is what is in it now…

Any thoughts?

Thanks…BCB

[Toymaker]

Not saying this is it, but this happened to a friend with an Encore and it took us an accident to discover the problem.
Really great accuracy when suddenly its gone. Poof. From sub-MOA to a shotgun pattern. Check the screws, check the mounts, check this, check that, clean the heck out of the barrel. Accuracy's back.....until it's gone again. Cease fire for a relay break, no handling of firearms. Go inside and grab a couple of books trying to find information on the issue. On our phones checking the internet for information. A good hour, maybe an hour and a half, has passed. Back to the bench and shoot a couple of rounds. ACCURACY IS BACK!!!
Accuracy is back, but the point of impact isn't quite where it was before. Keep shooting and watch the barrel temperature, by feel. When it gets hot and the blocks are warm, accuracy goes away. Take it into the range house (A/C) and let it cool. Accuracy returns, but POI is a little different. Shoot slow, keep the barrel from heating up too much and he didn't loose accuracy.

[David2011]

BCB, after reading Toymakers post, have you tried cold bore shots without removing the fouling?

[BCB]

BCB, after reading Toymakers post, have you tried cold bore shots without removing the fouling?

I never have, but I am not so sure the barrel was "hot". That is a very subjective thing. It was about 60 degrees temperature when I was shooting it and I was only firing 4 or 5 shots and not really quick as I have to lift the rifle from the bench to break it open, unload it, load it, position back on the sandbags and then shoot. The reloads are so lightly loaded that I don't even need to apply lube to size them--no hot loads...

The barrel was warm, but not what I would call hot...

Might be worth a try the next time it gets as fouled as it was in the photo posted. I did clean the barrel thoroughly but I haven't fired a round from it yet--Gotta love the Western PA weather...

BCB

[Smk SHoe]

Has the barrel had any jacketed bullets thru it? Could any machine marks from the rifling process be stripping lead off the bullet. I have had barrels that to 100-150 jacketed bullets thru it to settle down. Lead could be a lot more.

[BCB]

Has the barrel had any jacketed bullets thru it? Could any machine marks from the rifling process be stripping lead off the bullet. I have had barrels that to 100-150 jacketed bullets thru it to settle down. Lead could be a lot more.

Nope, no jacketed bullets. I bought the barrel strictly for cast boolits...

Compared to some T/C production barrels this MGM barrel looks as smooth as silk...

Thanks...BCB