Mini 14 cold bore change of impact.

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hend238

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Ok so I have a Mini 14 580 series ranch model that prints the first round from a cold bore, about 4" low and left. It doesn't matter if the barrel is clean or dirty. These first shots will all group quite nicely as well. All remaining shots will group around my point of aim. The rifle will continue to group at my point of aim mag change after mag change until I let the barrel cool.

This rifle is new and I have broken in the barrel and started load development. I've used the same powder, primers and cases but 4 different bullets so far in my development. Surprisingly some of my initial loads are grouping 9 shots under 2 inches which is pretty damn good, if you ignore the first shot from the cold bore. :bangHead:

So all of you Mini 14 gurus out there, do you have any words of wisdom?
 
Its a Mini 14....thats what they do. I tried to make sense of mine then just sold it. Load up some mags and let em rip and don't worry about trying to fine tune it.
 
I have owned many Mini 14's and 30's, some scoped and some not, I finally realized if you use a very small target and nail to the side of a barn you will prevent the bullet from leaving your property.
 
LOL. Fair enough guys. The thing is the first cold bore shot goes in exactly the same place every time. Something tells me this can be remedied or reduced. That fact that this rifle will group 10 shots around 2 inches at 100 yards compels me to search for an answer. It's too soon to accept failure as I haven't even tried to get it to shoot well. I'm hoping I can get some constructive input for this issue.
 
I hate to be the bearer of bad news, but I've never found a cure for your problem that didn't involve a new barrel. In the your case that pretty much means a new rifle. I had to return a Sako about a year ago that put the first one 2-3 inches high every time then the next four under an inch.

There's a reason why Bill Ruger called the Mini "The worlds most expensive plinker". When that's the highest praise the designer can come up with its time to quit.
 
Dogleg said:
I hate to be the bearer of bad news, but I've never found a cure for your problem that didn't involve a new barrel. In the your case that pretty much means a new rifle. I had to return a Sako about a year ago that put the first one 2-3 inches high every time then the next four under an inch.

There's a reason why Bill Ruger called the Mini "The worlds most expensive plinker". When that's the highest praise the designer can come up with its time to quit.
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A barrel eh? Bummer. I'll rule out bad bedding/inletting first.
 
A barrel strut strenghtens the barrel so heat will not effect your MOA as much. Google Har-Bar

Its like a splint :p Remember its a mini-14 and not a bench rest rifle anything under 4moa is golden. You dont see the SKS guys complianing their SKS is not 1 moa ;)

The biggest problem with the mini14 is people thinking its a HB Freefloating AR15

pimped_mini14.jpg
 
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Trust me I have no expectations of sub MOA performance. Not even maybe. I just want to try and eliminate that first shot going wild. If the rifle sprayed all it's shots then I wouldn't have even bothered posting this but that is not the case. The rifle performs in exactly the same way every single time. One low and left then a nice cluster at point of aim. The question is, is the first shot the problem or the remaining shots? What's causing the different point of impact? If I can determine that then perhaps the issue can be resolved to a level that is satisfactory when considering the limits of the Mini 14.

Thanks for the barrel strut idea. I'll check it out.
 
Also make sure the torque on your gas block is even and the gap is even on both sides

If you get a strut let us know if it helped :)
 
Dsiwy said:
Also make sure the torque on your gas block is even and the gap is even on both sides

If you get a strut let us know if it helped :)
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I'm checking out the Har-bar page now. Interesting concept. The theory is good but I wonder how effective it is. Yes if I buy one I'll let you guys know how it worked.

As for the gas block, the first thing I did before even firing the rifle was remove the block and true up the surfaces on a surface plate with 400 grit sandpaper. That took several hrs but I believe it was well worth the effort in the battle for consistency. When installing the block I used my torque wrench and feeler gauges to get the gap and screw torque equal.
 
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there is Accu-strut too but they will not ship to Canada, Which sucks as theirs is better looking on the gun
 
Do you have a wood stock or a Hogue stock? Had the same annoying little problem when I changed my stock. It is a very easy fix, but first, need to know what kind of stock and handguard. Do get too worries by all those folks whom love to lob hate grenades at the Mini because it can't hit a nickel at 600 yards.

After
Picture001-19.jpg


Before
Picture001-12.jpg
 
Factory Hogue stock and hand guard as removed from the box. Simple fix eh? The suspense is killing me. As for the hate grenades, I have thick skin.
 
First thing with the handguard. It clips onto the barrel AFTER insertion into the housing on the gas block assembly. It should be free to "wiggle" and not make contact with top of that assembly, particularly with the stock inserted. When I replaced my handguard (with the wood stock), I thought the fit had to be snug, because that was how it was with the original. When I replaced the stock with the new one, that snug fit proved to be an epiphany for me as I experienced the exact issue as yourself.

So, firstly - with the stock removed, check the handguard and undertake some light sanding and or trimming if there is excessive contact. The handguard (when affixed to the barrel) should have some play when it is set into the gas block assembly. Next comes the tricky part.

The Hogue stock is basically a pliable rubber coating over a plastic skeleton. There is a metal liner, which fits over the stock and is inserted into the gas block assembly as well. You will note that it is a stamped contraption and has marks all over it from compression (pressure) as opposed to friction from movement. My rifle also had friction marks where the slide assembly made contact with this liner. When fitting the stock into the gas block, it fit quite snugly sliding into the gas block even before the receiver was in contact with the stock. At this point in time, the gas block was acting like a fulcrum and pressure from the stock/liner assembly was being exerted. This pressure is relieved as the block warms up after a few firings and metal starts to expand.

To relieve this, I took a pair of adjustable pliers, and gently "squeezed" the liner tighter to the stock and filed away excessive points of impact. After repeating this process several times until the stock would insert into the gas block assembly without undue pressure. I also lightly taped the liner tabs (making direct contact with the gas block as I noted the lower one (in particular) was making almost full contact with the gas block. I lightly sanded the surface of liner tabs and lightly greased - just because I like to - to ensure that there was not any uneven pressure.

Lastly, I undertook some light trimming on the stock to ensure that there was no binding or pressure points between the handguard and the stock. When the trigger guard is affixed, my handguard will "wiggle" slightly in vertical movement.

My groupings improved immensely and the bullet wander went away. That was my solution. I also discovered that the rifle adapts very well to the Winchester 64 gr psp bullets with about 25 grains of Win 748 powder.
 
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Sobo my friend you are my hero. I won't be home for a few more months but as soon as practical I will investigate as directed. What you are saying makes absolute sense to me and I can picture every detail you described. This little piece of info you have given me is by far the most useful and insightful thing I have learned from this site. Thanks to you and the others who provided constructive feed back. I'll be sure to update this post when I get things sorted.
 
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