M14 Forum banner
1 - 20 of 57 Posts

·
Registered
Joined
·
249 Posts
Discussion Starter · #1 ·
I'm kind of at a loss here. The first shot in every five-shot group ended up about 2 inches higher than the rest of the group at 100 yards. The other 4 in the group were usually decent. I was doing a load progression with IMR 8208 XBR from 39 to 41 grains with commercial (WInchester) cases and SMK 168gr. All groups were right and above the dot I was aiming at. The best group (after the initial shot) was with 40.5 grains, where they were all just about overlapping. I only shot one five-round group with each charge weight that day, each time giving the rifle about 10 minutes in between to cool off. I'll also note that I didn't see any overpressure signs with any of the charge weights (just slightly-flatter primers), so I'm tempted to go a little higher next time (Hodgdon site says max 43.3gr for 308-type load).


My only guess for what might be causing this is the difference in cartridge seating compared to when I rack the bolt for the first shot and when it autoloads after successive shots. Any ideas? thanks!











 

·
Registered
Joined
·
249 Posts
Discussion Starter · #2 ·
By the way, info on my rifle found here: http://m14tfl.com/upload/showthread.php?t=90857

The only thing I've changed since then is filing down the fiberglass handguard so it doesn't rub on the stock, and lubricating the ferrule with some lithium grease.

And also, the rifle wasn't really moved or handled much between groups, the magazine was just removed, refilled, and replaced. The rifle was shot from bags as well.
 

·
Registered
Joined
·
174 Posts
Remember, the Hodgdon data is for a 308 using a bolt-gun. You are using a 7.62x51 with an M14. NOT the same animal. You need to keep pressures at or below 50,000 PSI for that rifle. I'd say stick with the 40.5 grain load since it's working well. Also, notice how the primers are flattened at the end of the scale. This is an indicator that your rifle is showing pressure signs, not necessarily top pressure for the cartridge. Bolt guns can operate at higher pressures; semi's cannot.

As far as the first round "flyer". That's common with most rifles, be it semi or bolt. Your's is a little more than some, maybe less than others. It's still annoying, I know, and perhaps you could change mags as a process of elimination. How are you releasing the bolt on a fresh mag? Are you using the op-rod handle, or releasing the bolt (if you have one) with the Smith Oversized Bolt Release?
 

·
Registered
Joined
·
558 Posts
Personally, I think 168s are a little too heavy for IMR 8208's relatively faster burn rate than the usual suspect powders for the 14, like 4895, 4064, but your question is one that has been debated to no end. It not uncommon.

My belief, since it seems to make the most sense to me is that the harmonics of the barrel change when heated and the diameter of the bore changes as well. The change in temperature of the steel, especially closest to the bullet, the exposed bore steel, will be "greatest" going from a cold bore to the first shot, than from the first shot to a subsequent one.

You have to rule out all other things too, like flinching more on the first shot, etc, but Ive experienced the same phenomenom as well, and so have many, many others and debated the causes endlessly...
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #5 ·
Remember, the Hodgdon data is for a 308 using a bolt-gun. You are using a 7.62x51 with an M14. NOT the same animal. You need to keep pressures at or below 50,000 PSI for that rifle. I'd say stick with the 40.5 grain load since it's working well. Also, notice how the primers are flattened at the end of the scale. This is an indicator that your rifle is showing pressure signs, not necessarily top pressure for the cartridge. Bolt guns can operate at higher pressures; semi's cannot.
Personally, I think 168s are a little too heavy for IMR 8208's relatively faster burn rate than the usual suspect powders for the 14, like 4895, 4064, but your question is one that has been debated to no end. It not uncommon.
I'll tend to agree with you that the powder isn't ideally suited for the bullet weight, however, I like to experiment GI2. I bought some 150gr SGKs I'd like to try later on as well, which would probably be better for this. I'd like to have as near to a compressed charge as possible. Where I live, the weather climate can change from fairly hot 90 degree summers to fairly cold 10 degree or below winters, so I was looking for a charge with VARGET or XBR that would give good temperature insensitivity.

It's funny though, I've seen much flatter primers on DAG 7.62NATO ammo, although they are berdan primed, so maybe that is to be expected?

As far as the first round "flyer". That's common with most rifles, be it semi or bolt. Your's is a little more than some, maybe less than others. It's still annoying, I know, and perhaps you could change mags as a process of elimination. How are you releasing the bolt on a fresh mag? Are you using the op-rod handle, or releasing the bolt (if you have one) with the Smith Oversized Bolt Release?
Maybe next time I'll leave the magazine in and load the rounds through the rifle. I've also been using a 10-round mag, maybe a 20-rd would give more constant upward force on the cartridges for the 5 rounds? I rack the bolt by pulling the op-rod all the way back and letting her rip.

My belief, since it seems to make the most sense to me is that the harmonics of the barrel change when heated and the diameter of the bore changes as well. The change in temperature of the steel, especially closest to the bullet, the exposed bore steel, will be "greatest" going from a cold bore to the first shot, than from the first shot to a subsequent one.
I hope it's not that, cause there won't be much I can do about it, save for maybe an expensive barrel replacement GI3. (College-student budget here) I was debating finding a synthetic stock and getting it bedded (want to preserve the really beautiful original walnut stock), do you think that would be worth it? (might run me $200-250)

You have to rule out all other things too, like flinching more on the first shot, etc, but Ive experienced the same phenomenom as well, and so have many, many others and debated the causes endlessly...
I won't admit to being a perfect shot, but I can't convince myself that I was flinching 2+ inches every single first shot. I'll keep looking into it, hopefully it won't drive me crazy.
 

·
Registered
Joined
·
335 Posts
Try using only 5 round magazines for groups. My rifle used to do that with 20s and 10s - maybe its just my rifle that only likes 5 rounders though. I also found that if you are shooting off a bench make sure the middle of the forestock is on the front rest and the front sling swivel is not touching the front of the front rest pad. For my rifle it makes a difference.
 

·
Registered
Joined
·
9,809 Posts
It is not uncommon to see a flyer like that with a standard weight barrel, I have a standard and I will get flyers like that too. The only way that I have gotten around the problem is to wait several minutes between each round, you have to fire each shot as a cold barrel shot. I don't want to spend the money on a heavier barrel so I just deal with the problem.

As for the 8208 powder, check out this link; http://m14tfl.com/upload/showthread.php?t=85821&highlight=8208. This link is about some of the results that several of us are getting with the powder using bullet weights from 125 to 168 grains.

As for the 168gr bullets, one poster in that link included a photo of a group he got that is one hole and I have personally gotten groups as tight as 0.5" at 100 yards out of my SOCOM 16 so very good groups can be obtained.

The problem that I have noticed so far (using 168gr bullets) is that the powder charge weight range is relatively short, my experiments tend to indicate charge weights of 38 - 40.5 grains would equate to using 93% - 100% of case capacity in most situations. Also, the chamber pressure will jump from a safe value to dangerous levels pretty quickly when you get to the top end of the charge weights.
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #8 ·
I'm guessing that if 40.5 grains filled it up, you were using military-spec brass? Mine weren't near full at 41 grains, and I was using commercial. That would also explain the large pressure differences.

I think I may give the 8208 another chance with the lighter bullets, but stick with a more conventional load for the heavies.

Thanks for the link.

As far as the barrel is concerned, I would really like to be able to put two successive rounds on target (otherwise, what good is an autoloader), so I may look into a heavy barrel, or maybe something like bedding to dampen the barrel harmonics. Ideally, I'd like the JAE stock with the barrel tensioner, but that is a huge investment.
 

·
Registered
Joined
·
9,809 Posts
I'm guessing that if 40.5 grains filled it up, you were using military-spec brass? Mine weren't near full at 41 grains, and I was using commercial. That would also explain the large pressure differences.

I think I may give the 8208 another chance with the lighter bullets, but stick with a more conventional load for the heavies.

Thanks for the link.

As far as the barrel is concerned, I would really like to be able to put two successive rounds on target (otherwise, what good is an autoloader), so I may look into a heavy barrel, or maybe something like bedding to dampen the barrel harmonics. Ideally, I'd like the JAE stock with the barrel tensioner, but that is a huge investment.

I am using Lapua brass which close to military spec in regards to volume. What brass are you using and what trim to length? I can give you some numbers to work with, I can run your stuff through my QuickLOAD software and see what it says.

The JAE does help, I have one and my flyer doesn't show when I use the stock. I have switched the stock between my standard rifle and my SOCOM and it seems to resolve the flyer problem. I am in the process of getting another JAE for the second rifle.

P.S.
I just ran a quick check in QuickLOAD using my info on Hornady brass. 41gr with their brass trimmed to 2.005" and using a Hornady 168gr A-Max would only load the case to about 93% capacity, so you're right, there would be a big difference in capacity. In this case 44 grains would take it to 100% of capacity but by then the chamber pressure would be up around 63,000 psi.
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #10 ·
It was Winchester brass, new from the bag, sized in a single-stage LEE press. I trimmed to 2.005", and seated to a COL of 2.805". I know my chamber will accept quite a bit a longer COL (I would have liked to seat for a 0.020" jump), but that was about the biggest that would comfortably fit in the magazine.

I am envious of the stocks! GI1 Wish I had a real job so I could blow some green on that.
 

·
Registered
Joined
·
558 Posts
--------I hope it's not that, cause there won't be much I can do about it, save for maybe an expensive barrel replacement GI3. (College-student budget here) I was debating finding a synthetic stock and getting it bedded (want to preserve the really beautiful original walnut stock), do you think that would be worth it? (might run me $200-250)---------

Your missing the point. Physics is physics. The "cold bore" shot dilemma is a fact of life. Yes, you can do things to lessen the group spread, but its an issue everyone deals with on some level when it comes to placing the first shot and all subsequent shots in the same tiny little place. Im not saying thats why you are getting that flyer. Maybe it is, maybe it isnt, but your expectations are probably a little high. You are not dealing with a custom BR bolt action, nor are you dealing with an ultra accurate round, the .308 Winny, but neither is anyone else. Gas guns, will on average magnify any error in the possibility of putting 5 shots in the same place. The first shot will usually be the farthest from the central tendency of the group, on average. Will upgrading your rifle to match grade status lessen the spread? Yeah, to some degree, but ultimately it comes down to the sinister specter that haunts everyone, match shooters to Marine snipers. That specter being whether or not the first shot goes where it is intended to and will follow-up subsequent shots stay close to it, or wind up someplace else.

If you ever read about when Hathcock was training future snipers, he would often get them all set for a day on the range. He would take them out, they would get all their gear out, get into position and fire a shot, and then Hathcock, after that first shot, would tell them to take some notes, pack it up, they were done for the day, meet again in the morning. He would do this for a good long time, because he knew and explained to them that this was about understanding what their rifles were going to do when they took the shot that counted, and that any subsequent shots would not be in the same place as the first , and any further shooting that day was irrelevant.

As a barrel heats it expands. As it expands the diameter of the bore expands. Shoot a bullet same weight, same speed, same pressure, out of two equally made barrels, one cold, one warm or hot and the bullet is going to impact in a different place. As the temperature of the barrel starts to "even out" (to some degree), groups begin to tighten. If we could somehow keep the bore a constant temp (and level of "fouling" he same), dispersion would drop dramatically.

Nevertheless, these are subjective meanderings, to "some" degree, on my part, but I believe them. I dont know whats causing that one first shot to shoot high, its probably a combination of what Ive said above and 100 other variables, but what we call a "cold bore" shot is an aberration we all contend with to some degree...

NOTE: Cold Bore, to me, means more than just a "cold bore". Its a relative term. It really means a temperature differential, whether you start cold and go warm, or start warm and go hot, or start hot and go till your barrel turns white, dispersion happens. In some cases a little, in some cases, a lot. But like Hathcock said to his students, its knowing that "something" does happen and knowing is the key to understanding how the shooter has to compensate...DI2
 

·
Registered
Joined
·
558 Posts
As for the 168gr bullets, one poster in that link included a photo of a group he got that is one hole and I have personally gotten groups as tight as 0.5" at 100 yards out of my SOCOM 16 so....

How often and how many rounds made up each of the groups?

0.5" is awfully small to call it a done deal. I would call it "quite possible, but highly unusual" from the given platform and for groups with 5 rounds or greater..

Does it happen? Yeah, but does it happen often enough to call it "expected"....?

One hole groups? With a 14? Are we talking about 5+ rounds or 2? Are we talking about a weekly event or something that only happens when the year divides evenly by 3?

Again, a single aberration ("a great day on the bench"), does not make for what can be reasonably expected. One target says nothing...Not knocking it, but it doesn't mean anything...
 

·
Registered
Joined
·
9,809 Posts
It was Winchester brass, new from the bag, sized in a single-stage LEE press. I trimmed to 2.005", and seated to a COL of 2.805". I know my chamber will accept quite a bit a longer COL (I would have liked to seat for a 0.020" jump), but that was about the biggest that would comfortably fit in the magazine.

I am envious of the stocks! GI1 Wish I had a real job so I could blow some green on that.
Unfortunately I don't know the volume on the Winchester brass but I did find a post on the Inet that said 57 grains was the average volume. That's actually more volume than the Hornady case I mentioned. If you want some specific numbers we can talk via private mail and we can exchange info. For the volume you weigh the empty brass (with used primer in place and trimmed to length without resizing) and then you fill the brass with water and weigh it again. The weight of the water is used by the software to interpret the volume. The software is not perfect it usually comes up with numbers that are pretty close to the real world results.
 

·
Registered
Joined
·
9,809 Posts
As for the 168gr bullets, one poster in that link included a photo of a group he got that is one hole and I have personally gotten groups as tight as 0.5" at 100 yards out of my SOCOM 16 so....

How often and how many rounds made up each of the groups?

0.5" is awfully small to call it a done deal. I would call it "quite possible, but highly unusual" from the given platform and for groups with 5 rounds or greater..

Does it happen? Yeah, but does it happen often enough to call it "expected"....?

One hole groups? With a 14? Are we talking about 5+ rounds or 2? Are we talking about a weekly event or something that only happens when the year divides evenly by 3?

Again, a single aberration ("a great day on the bench"), does not make for what can be reasonably expected. One target says nothing...Not knocking it, but it doesn't mean anything...
Assuming the best interpretation of your comments leads me to the conclusion that I should thank you for your compliment since I did get a 5 round group of a half inch firing 168gr bullets at 100 yards with my SOCOM 16. I guess it is unique and I should be proud of my singular accomplishment. Then again, do you just have poor communication skills and seem to say the wrong things all the time? I'm not trying to be rude but your remarks seem to basically call me a liar on a public forum which isn't very conducive to a civil conversation. Try asking questions about my process if you think it is unusual rather than making a bold statement as if I were lying.

If you had read the link that I referred to you would have seen that the picture of the one hole group was not the result of shots fired from an M14 platform. But my point (which I thought was obvious) was that the 8082 powder can give you very good groups using the 168gr .308 caliber bullets. What can reasonably be expected with a 22" standard barrel is impossible to say considering the number of variables involved. But if the shooter knows what he is doing, and the rifle is working well, and the weather conditions are good, 1" or better groups are perfectly possible with this powder and 168gr bullets at 100 yards from a bench, using sand bags.

As for you implication that I had a one time fluke, do a little searching on this forum and you will find that I have stated that my normal groups are about an inch plus or minus a quarter inch at 100 yards from a bench but I have gotten half inch groups more than once. The one half inch group was not an average group for my SOCOM but it does indicate that the 8208 powder can create some good groups even though I used a heavy bullet in a short barrel. So, on the contrary, it demonstrates that it is a fact that it is possible to get this small of a group. Even if it isn't the normal group size it is impressive to me that it can be done at all. I would explain my grouping process in detail if I thought that you had a real interest in exchanging information but somehow I get the feeling that you are more interested in telling people things rather than listening to their point of view or experiences.
 

·
Registered
Joined
·
1,198 Posts
It was Winchester brass, new from the bag, sized in a single-stage LEE press. I trimmed to 2.005", and seated to a COL of 2.805". I know my chamber will accept quite a bit a longer COL (I would have liked to seat for a 0.020" jump), but that was about the biggest that would comfortably fit in the magazine.

I am envious of the stocks! GI1 Wish I had a real job so I could blow some green on that.
I would think it would be tough to get .020" jump I seat my 168 Nosler CC's at 2.260" (base to ogive) and I am at .030" jump and that as far as I can go due to mag length
 

·
Banned
Joined
·
2,325 Posts
shots

If you will factory crimp your rounds, I believe your first shot meandering will be controlled...personally I have no belief in the cold bore shot syndrome...I have 3 M14 rifles,.1- M1a from springfield, 1- 7.62mm firearms I built with c clamps and wood, and another SAI barreled action I built....every one of them will shoot groups first time and all day from the bench or prone, or whatever position if I do my part, with no flyers.

I regularly shoot sub MOA groups with all three, most times a ragged hole where the X use to be and couple weeks ago shot a nickel size group of six shots. All my rounds are handloads and factory crimped, the barrel is dry patched only and sometimes not at all before shooting if I forget or didn't heavy oil it when putting it away. I also clean my rifles after every range trip....down to the metal and with copper solvent...everytime.

Also check the gas cylinder and stock ferrel for rubbing or shiny spots, it causes more problems than anything.
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #18 ·
I know 1 MOA is no easy feat for the M14, but, I would like to at least try to get there. First step I spose is to realize what is causing that flyer, then decide what I can do to fix it, if I can fix it, and then if so, figure out if I can afford to fix it.

I'm pretty sure not everyone sees the first shot flyer issue, not to confuse it with the fouling shots (which I did do even before the first group, then let cool) - so, I think it is fixable.

Ripsaw, how does the crimp fix the problem? I have some factory crimp dies, and could load some cannelured bullets to try it out.
 

·
Registered
Joined
·
558 Posts
Assuming the best interpretation of your comments leads me to the conclusion that I should thank you for your compliment since I did get a 5 round group of a half inch firing 168gr bullets at 100 yards with my SOCOM 16. I guess it is unique and I should be proud of my singular accomplishment. Then again, do you just have poor communication skills and seem to say the wrong things all the time? I'm not trying to be rude but your remarks seem to basically call me a liar on a public forum which isn't very conducive to a civil conversation. Try asking questions about my process if you think it is unusual rather than making a bold statement as if I were lying.

If you had read the link that I referred to you would have seen that the picture of the one hole group was not the result of shots fired from an M14 platform. But my point (which I thought was obvious) was that the 8082 powder can give you very good groups using the 168gr .308 caliber bullets. What can reasonably be expected with a 22" standard barrel is impossible to say considering the number of variables involved. But if the shooter knows what he is doing, and the rifle is working well, and the weather conditions are good, 1" or better groups are perfectly possible with this powder and 168gr bullets at 100 yards from a bench, using sand bags.

As for you implication that I had a one time fluke, do a little searching on this forum and you will find that I have stated that my normal groups are about an inch plus or minus a quarter inch at 100 yards from a bench but I have gotten half inch groups more than once. The one half inch group was not an average group for my SOCOM but it does indicate that the 8208 powder can create some good groups even though I used a heavy bullet in a short barrel. So, on the contrary, it demonstrates that it is a fact that it is possible to get this small of a group. Even if it isn't the normal group size it is impressive to me that it can be done at all. I would explain my grouping process in detail if I thought that you had a real interest in exchanging information but somehow I get the feeling that you are more interested in telling people things rather than listening to their point of view or experiences.
My point is that when someone says "I got a .5" inch group (or one hole group).....", it isnt helping the person trying to figure out why his groups look the they do. Its saying "hey look what I did, once (or twice), you should get the same". Well, unless .5 inch groups are your norm (you did not state your norm), what are you telling this person? "Look what I can do", or "This is what you should be doing"? To say "go find some of my other posts where I state 1.25 or whatever is my norm", NOW , only after I made my comment, just proves my point. 0.5 is not a norm, but the OP would never have known unless someone said something.

Im not knocking your ".5 achievement", Im pointing out that 1) If it happens once, its not something the OP should expect on average, and 2) without any further information it doesn't help him and might even cause him to lose faith altogether....

We are dealing with M14s and .308 Winny folks! Not lasers....
 

·
Banned
Joined
·
2,325 Posts
fix

I know 1 MOA is no easy feat for the M14, but, I would like to at least try to get there. First step I spose is to realize what is causing that flyer, then decide what I can do to fix it, if I can fix it, and then if so, figure out if I can afford to fix it.

I'm pretty sure not everyone sees the first shot flyer issue, not to confuse it with the fouling shots (which I did do even before the first group, then let cool) - so, I think it is fixable.

Ripsaw, how does the crimp fix the problem? I have some factory crimp dies, and could load some cannelured bullets to try it out.
RVpilot...yes , it is a Lee factory crimp die...

Brick, I believe the action of the bolt when cycled by firing and the action of first round loading by you pulling op rod back are two different things...hence the shot pattern...The factory crimp will just hold the projectile more static upon loading.

I really think you need to look at the front ferrel inside the stock and the stock in back where the receiver sits, is it evenly shiny under the receiver ? Indicating that it is bedded down and clamped evenly when trigger group is latched,....the gas cylinder hitting anything up front...the sides of the stock or the ferrel will give these type groups....everytime....It cost nothing to fix it...just a round chainsaw file. You can file the ferrel down so it doesn't hit GC..and file the inside of stock at 3 and 9 o'clock if its shiny and been hitting....please post pics of inside ferrel and bottom of gas cylinder ???...If it has enough slop to hit the ferrel...you may also have a draw pressure issue...you can search that term here for much more reading and a quick and easy fix for draw pressure.
 
1 - 20 of 57 Posts
Top