theory behind accurizing techniques?

na1lb0hm

na1lb0hm

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Well first off, I'm new to the m305/m14s game, bought one 6 months ago, shot it twice, got discouraged, put it back in the safe. Quite frankly, feeling way over my head and outta my league on this stuff.

I've read about the gas system unitizing and shimming the gas cylinder in the faqs, but wondering about the theory behind them.

Things seem to click better when I understand WHY, not just HOW.

thanks guys
 
na1lb0hm said:
Well first off, I'm new to the m305/m14s game, bought one 6 months ago, shot it twice, got discouraged, put it back in the safe. Quite frankly, feeling way over my head and outta my league on this stuff.

I've read about the gas system unitizing and shimming the gas cylinder in the faqs, but wondering about the theory behind them.

Things seem to click better when I understand WHY, not just HOW.

thanks guys
Click to expand...

What happened when you took the rifle out?
I haven't gone the modifying route because with cheap ammo I am getting 3 1/2" groups at 100m. I am afraid to spend a lot of money to find I'm only shrinking the groups by an 1"-1 1/2" at 100m. The sights are the worst weak point for me; I would get a quality (Sadlak, Arms18, Promag Arms 18) scope mount, a proven quality optic, and see how it shot then. I read a review of a high end 308 AR that shot between 1.5" and 2.8" at 100 yds with premium ammo. If you have a chance, put your M14 on a bench or solid rest set up and see what it is actually capable of in stock form. Or get an experienced open sight competitor to wring it out for you. Yes, these rifles are cheap and clunky, but often they perform very well in stock form. The question you need to ask yourself is, does a truck work better in normal use with $10k of lift, tires, and wheels? Maybe it would be more fun to shoot it than spend $$$ building it.
 
What discouraged you?

The basic theory behind the accurizing effects of unitizing is that parts that move about have an inconsistent influence on the barrel, which translates into inconsistent accuracy. The parts that influence the barrel need to either stay put, or move in a consistent mannera and return to the same position and influence on the barrel after each shot. It's like shooting during gusts of wind. You can adjust the windage all you want, but if the wind blows hard on one shot and doesn't on the next, the influence of the wind will be a variable. Since the stock and components of the gas system all influence the barrel, they need to be made consistent by being tighter in some cases (gas system to barrel), or smoother and returning to the same position each shot in other components (stock, ferule, barrel band).
 
na1lb0hm said:
Well first off, I'm new to the m305/m14s game, bought one 6 months ago, shot it twice, got discouraged, put it back in the safe. Quite frankly, feeling way over my head and outta my league on this stuff.

I've read about the gas system unitizing and shimming the gas cylinder in the faqs, but wondering about the theory behind them.

Things seem to click better when I understand WHY, not just HOW.

thanks guys
Click to expand...

what do you want out of your m14s??? For shooting tiny groups i revert to the rem 700, for fun, off hand shooting, hunting, etc the m14 is number 1, tweaking the m14 is easy if you have any mechanical skills, start by staking the oprod guide, this is an easy tweek that will get the ball rolling, read the stickies, pretty much anything you need to know is in the stickies...good luck
 
Hi. There's not much point in spending a pile of money accurizing a rifle with a stock barrel. M305's aren't target rifles. Think hunting accuracy.
The best thing you can do is to use good ammo. If you tried milsurp, it's not loaded for great accuracy.
If you're not reloading, you'll have to try a box of as many brands as you can to find the ammo your rifle shoots best. The price of said ammo means nothing.
If you are, work up a load. Think 150 to 168 grain bullets with IMR or H 4895(close but not the same), IMR4064 or Varget.
 
I also consider myself a rookie at the M14 game having only had about 8 or 10 of the buggers LOL! In my view, the stock Norc is a good value rifle but a truckload of money can be spent ( as I have done ) only to find that accuracy is only reduced from 3" groups to just about 1.5" groups. I've gone most routes and I've ended up with the opinion that you either leave pretty much alone or buy one with a match barrel as most of the in-between fixes don't really improve much over the stock Norcs.

Now lots of folk will disagree with me on the above but that's my view after spending a pant load of cash on several of these rifles. Having said all that, if you have the money by all means spend it - it is actually pretty fun to build various configurations: I have an M14Doc 'shorty' now that I spent quite a lot of cash on and it is a great rifle to shoot. If accuracy is your game out of the M14 though, a match barreled M1A Loaded is hard to beat. Better yet, keep an M14 for fun shooting and a bolt gun for tack driving.

Last point, these rifles are very ammo sensitive and you may find that a simple load switch does more for accuracy improvement than anything else.
 
Tomochan said:
I also consider myself a rookie at the M14 game having only had about 8 or 10 of the buggers LOL! In my view, the stock Norc is a good value rifle but a truckload of money can be spent ( as I have done ) only to find that accuracy is only reduced from 3" groups to just about 1.5" groups. I've gone most routes and I've ended up with the opinion that you either leave pretty much alone or buy one with a match barrel as most of the in-between fixes don't really improve much over the stock Norcs.

Now lots of folk will disagree with me on the above but that's my view after spending a pant load of cash on several of these rifles. Having said all that, if you have the money by all means spend it - it is actually pretty fun to build various configurations: I have an M14Doc 'shorty' now that I spent quite a lot of cash on and it is a great rifle to shoot. If accuracy is your game out of the M14 though, a match barreled M1A Loaded is hard to beat. Better yet, keep an M14 for fun shooting and a bolt gun for tack driving.

Last point, these rifles are very ammo sensitive and you may find that a simple load switch does more for accuracy improvement than anything else.
Click to expand...

Great post Tomochan,......... I'd say pretty much sums up the M-14 experience. :canadaFlag:
 
My m305 shoots 1.5inch stock, and I'm not even impressed by that. This was before I put a new oprod guide in, and I'm about to shim the gas system. The next thing I want to do is get a stock for accuracy, and those Archangels are looking pretty nice, but I'm debating holding off for an m14-cqb from the doctor. I figure I'll get it down under 1.5inches with 150g hunting bullets, and that'll be badass.

Of course this won't stop me from getting an accurate bolt rifle haha
 
All of you are right with the bolt guns being far more accurate and reliably accurate than a super $$ tweaked M14/M1A platform. When I want precision, I turn to my "one of 4" Rem M700's, it just works that way.

When I want to see how my handiwork turns out, I turn to my Douglas barreled 2007 Norc for a source of pride and enjoyment. Just don't dump a pile of money into the M14 platform unless you severely think it over! :eek: Save your money and buy a bolt gun. BUT (big but here) if you want a truck gun or a zombie fighter :ninja: The M14 cut down is your ticket!! Now the M700 cannot come close at delivering the goods during the Zombie Invasion (October 2011 wasn't it calculated??) :nest:

Cheers,
Barney
 
Accurizing the M14 - yup! Why?...because I want to. I used Hungry's cheap method, except for the 7.62 bolt, to see just how good the rifle can shoot.

Am I going to win matches or shoot 1,200 yards, probably not. But you know what, it's a hoot knowing my rifle is an excellent shooter, much more so than I will ever be standing in the bush with it.

Also folks, speaking of cheap...I AM KING!!!

Shooting sticks go for about $60 or $70 here in Alberta. Telescoping ones, for way more than that. Telescoping, locking AND padded ones..I dunno, $200 or so.

Mine...$35...yes...$35. Got a painters stick (expanding) for $35. I had some 3/4" pex pipe, a 5/8" dowel piece and a hanging hook kicking around at home.

Cut the pex pipe to about 2" and screwed onto the paint stick. Took about 1-1/4" of the dowel, camfered the base a bit, and pounded it into the top of the pex pipe. Drilled a hole for the hanger and screwed it in. Bent the hooks out to fit my stocks...and voila! Cheap expandable shooting stick - expands to almost 6' or so and is very, very light! It is quite sturdy too! :D :D

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in terms of the stickies : read, re-read, studied, tried osmosis, everything short of printing off, grinding them up and injecting them directly in to my veins.

I was looking for WHY(theory/logic/applied), not how, you unitize the gas group/ shim the gas block. Does shimming the gas block prevent movement? insure equal pressure on the barrel? etc. etc.

The reason I am choosing these methods are because they seem like the best/cheapest way to start increasing accuracy. BEFORE I go ahead a spend more money into others.

in terms of my m14s experience:

well, first off it patterned rather than grouped, I think it is set crooked into the stock, scopes need massive amounts of adjustment to the left. Said it before, but any more creep in the trigger at it would be a registered ### offender.

I have an arms 18 mount, installed painstakingly, tried a falcon menace 4-14x44, bushnell elite 3-9x40, bushnell 10x40 on it.

Used both 150 grain remmy and federal. (no handloading for this guy yet...i know i know...)

This is with three different shooters at 100 yards off a bench,bags in the front, back pack under the back. (one of us might be a bad shot, but not all three!)

All the same result. +5 inch groups, I could live with 1.5-2.5, but not 5!

I'm not looking for bolt-gun groups or why someone would drop massive amounts of $ into their rifle. Been there, done that and unlike friends, family and wallet; I understand it just fine! haha.
 
Shimming the gas block produces consistent harmonic oscillation of the barrel. Assuming the ammo is consistent, then the bullet will exit the moving barrel at a consistent position and produce better groups. The barrel oscillates like a pendulum. If the bullet is released at different positions of the pendulum, you get a large group. If its always released at a consistent timing, and the pendulum oscillates or swings in a consistent manner, you get smaller groups. Your gun has a problem. 5" groups isn't right. If you fix the wrong things, you won't get much improvement. Either you go over everything with a fine tooth comb, or you are guessing at the solution.
 
Thanks Grizz, thats what I was looking for about the gas block.
also:
fine tooth comb it is then.

I don't want to give up easy, but I think about it, and it feels like I've gotta climb a mountain(learn all I can), battle dozens of hideous monsters (misinformation), hand build my sword from scratch(disassemble, reassemble, check everything over, identify problems) slay a dragon (trigger and mystery wood stock), to get to the princess (under 3 inch groups)
 
On the subject of shooting method: I would avoid putting a lot of stress on the forend of the stock. Because the barrel is influenced by the stock, through the barrel band, placing pressure on a front rest or bipod affects point of impact. Try to rest the stock closer to the magazine on a front rest, and don't use a lot of pressure. Also, let the barrel cool down after 5 shots to get the least influence from heat during your testing. If find after 20 or so shots, accuracy starts going to pot as the barrel heats up and probably warps.
 
Grizzlypeg said:
On the subject of shooting method: I would avoid putting a lot of stress on the forend of the stock. Because the barrel is influenced by the stock, through the barrel band, placing pressure on a front rest or bipod affects point of impact. Try to rest the stock closer to the magazine on a front rest, and don't use a lot of pressure. Also, let the barrel cool down after 5 shots to get the least influence from heat during your testing. If find after 20 or so shots, accuracy starts going to pot as the barrel heats up and probably warps.
Click to expand...

always do so, with the bags normally two inches ahead of the magwell, on all rifles.

reading a bit more, its looking like my barrel indexed improperly. going to double check tonight. and if so, its to the gunsmith and getting shorty-d as well. truck gun.

does the gas system unitizing follow the same logic as the shimming of the gas block?


is there anywhere you can point me towards a link/info with the differences (if any) between a newer (2007) m14s vs. m305? I've searched on here with no luck. EDIT: don't worry found lots. many popping up today.
 
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