Picked-up a Nice LR Rifle!

[GeneFrenkle]

Anyone want my copy? Trade it for an AR! LOL

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[gunderwood]

Haven't read that book, but I have Understanding Firearms Ballistics, 6th ed. by Robert Rinker. Picked it up a while ago at B&N for about $45. I did a search on Amazon for it, but the price is crazy: http://www.amazon.com/Understanding-Fir ... 115&sr=8-2

I have lots of others such as: Modern Exterior Ballistics: The Launch and Flight Dynamics of Symmetric Projectiles
http://www.amazon.com/gp/product/076430 ... UTF8&psc=1

It is one of THE classic ballistic works ever printed. However, that's very academic and unless your an engineer, mathematician, or physicist the book is worthless. Even then, what you will get out of it is a great understanding of ballistic modeling history, various simulations, etc. for building ballistic calculators. You won't get good practical information on using the knowledge for shooting.

This is also a good one: New Exact Small Arms Ballistics: The Source Book for Riflemen
http://www.amazon.com/gp/product/097499 ... UTF8&psc=1
A really good simplified model approach and if you Google it, you'll still find several of Pejsa Excel models for free.

However, Litz's book tops them all. He covers the theory at a high enough level that everyone can understand it, yet deep enough to get the important points so you can actually understand the output of the calcs. He also covers practical shooting application of the theory, includes a free Java calc, and gives instructions for how to use it to demonstrate various points of theory in the book. Also great for validating your use of a more field orientated calc since you have Lita'z calc, specific instructions, and results provided. Just plug the same thing into your field calc and the two should be very close.

Can't recommend it enough and no, I'm not associated with Litz in any way or get any kickbacks.

[gunderwood]

That is some amazing info and very helpful. I learned a lot just reading your post. The book should be pretty awesome.

Glad to help. Any chance you can get me off your DHS crazy lists? /jk

I have been reading other random forums where people are complaining that 168's are dropping to fast on target, leading to a need to make large adjustments while doping from 650-700 to 1000 or the inverse.

Large adjustments are indicative of a poor trajectory. The ballistic coefficient [BC; basically a relative measure of how much drag a bullet has...higher is better, but be careful as different reference curves are not comparable. e.g. G1 (most common) vs. G7 (the best for long range and rarely given)] isn't the best you can do in acceptable .308Win bullet weights for long range. However, the 168 SMK (a specific bullet which is likely what they mean by 168s, but there are lots of different 168s available...that's just the mass of the bullet) is VERY accurate until it hits the transsonic region. That boat tail design reduces buffeting right after the barrel releases the bullet, so 168 SMKs typically are more accurate than the better, longer range 175 SMKs.

What really matters is Danger Space. The military came up with it and it is the ONLY absolute measure of trajectory for comparison. Everything else (max Point Blank Range, drop, velocity, etc.) is more or less correlated to a good trajectory, but can lie. I'll post a DS example later.

I really have two goals in mind. One is to enjoy poking holes in paper at 1,000 yards a few times a year.

Sierra MatchKings, due to the ogive design and quality manufacturing, are almost your best bet. There are other more expensive options (e.g. Bergers VLD, Lapua Scenars), but SMKs are forgiving of seating depth and are the go to bullet for most paper punchers due to the fact they shoot well in many rifles. For an 18" .308Win, the go to bullet is the 175SMK and it is what the military loads in the MK 118LR.

Once again the 175gr Sierra Match King was selected as the bullet choice as well as new powder. But this time a unique ammunition manufacturer would be selected to load the ammo based on their merits. The Federal Cartridge Company was awarded the contract and the ammunition was designated the M118 Special Ball Long Range Mk316 Mod 0. Like with the M118LR, the name was just modified to keep from having to go through full classification for the new ammunition. Federal designed a new match case based on their Gold Medal Match cases and used a modified extruded propellant. Unfortunately the details of which propellant and the charge weight are not widely known at this time. Federal also uses their Gold Medal Match primer for this load. Essentially it is a specialized commercial load adapted for the military specifications. Part of the requirements also included much higher quality control measures which are probably nothing more than what Federal currently does on their commercial Gold Medal Match manufacturing line. Initial accuracy tests on the early production lots have been excellent with accuracy coming in at about .5 MOA at both 300 and 600 yards.

The Mk316 ammo is in the process of replacing the original M118LR ammo but it is unknown how long a full replacement will take, not to mention that there is already a Mod 1 (and probably Mod 2) versions of the ammo already being worked on and prepared for production. The special operations forces are getting the latest developed equipment and a lot of the information can be hard to come by without being in the right channels and you can rest assured that continued development will happen with venerable M118.
http://www.snipercentral.com/m118.phtml

Roll your own if you reload or just pick up 175SMK Gold Medal Match / Mk 118LR. The commercial loading IMHO is still better than the military unless it's the Mod 0. Then they're about the same. Just don't buy military rejects as that means the lot didn't pass inspection. It's safe to shoot, but the accuracy won't be great. Terminal performance of the SMKs are hit and miss. If they tumble early it's great, otherwise you get a .30 caliber hole and not much else. Military doesn't care because they are unreasonably (IMHO) restricted from using expanding bullets. Mk 316 is the newer version.

http://www.dtic.mil/ndia/2009infantrysm ... ii8524.pdf

Mk 319 SOST is a barrier blind load based on custom Barnes bullet. Would be an excellent all around cartridge for your AR10, but as far as I know you can't buy the bullets (yet?) to roll your own and the surplus supply isn't great as it's rejects. Not to mention it's very expensive when you can find it. Like all bullets with good terminal performance, accuracy is less than the match grade bullets such as the SMK. It's a lot lighter than you'd expect like all Barnes bullets due to the high/exclusive use of copper. I haven't seen enough glass tests for the SOST to replace the 165gr AccuBond though. If the military ever adopts this so it's a lot cheaper, this is the round I'll be stockpiling for my AR10 (similar role as yours...gap filler between my <200m 5.56mm ARs and the big boys .338LM/.50BMG).

The other is to learn and become proficient at long range SHTF engagements. I really want an MRAD 98 or AR30 that fires a 338 Lapua for that purpose. I figured this could be a great stop-gap piece while I learn and see if I have or can acquire the discipline before spending $8k-$9k on a rifle and glass.

Good choice of rifle. I have plans (one of these days) for a mid-caliber ultra light tactical bolt rifle (carbon fiber, short barrel, light optics, etc. total weight ~8lbs) for a more accurate package that fills the same role. Obviously gives up speed and CBQ options like an AR10). Riots are a good example where you might be legally justified in reaching out and touching someone for SD; particularly if you organize around defending your neighborhood.

My three favorite rounds for this are:

147gr NATO surplus or reloaded equivalent (let's face it, it's relatively cheap to stockpile, you might find some "laying around" during SHTF, so learn how to shoot it)

165gr BT/AB for amazing terminal performance and barrier shots. Flys the same, so dope doesn't change.

130gr Mk 316 SOST for barrier shots and can replace the other two if it wasn't so darn expansive.

IMHO, keep the optics small and light, but don't forget about possible CBQ requirements. E.g. ACOG/VCOG, any of the various 1-6x or 1-8x optics with a red dot function. Don't try and set it up for 1k shots only, find a balance so it really is a gap filler and not just a long range only semi-auto.

[MarcSpaz]

Well... I am never buying a used gun again unless the owner takes me to the range to run 100 rounds of ammo through it. I'm pretty PO'ed because I think the guys at the store knew this gun was defective. They made it very clear that they did all the customization work on the gun, they knew the person they bought it from and vouched for it a bit strong.

Bottom line... It had an M4 carbine buffer and spring, which is way too light and short for the 308. The mag catch/release was not properly installed. The ejector spring is too big/tight causing the bolt to not catch the cartridge, but just rest on top of it. The one mag it came with was worn and misshaped. The upper and the barrel are damaged from repeated bolt/ammo jams and they may need to be replaced.

I may be looking at the cost of a new gun just to have this one repaired. Makes sense if all I can use is the lower. I won't know for sure until I do the less expensive repairs and testing it again.

If you want the back-story... read on.

Before I went to the range, I chambered and ejected a few rounds to check the action out. It was very sticky on the manual eject requiring two hands. It also would not correctly feed a round after ejecting one. The bolt assembly would stay stuck open about a half inch with the round stuck in the chamber and the bolt assembly locked up in the upper.

I did a tear down and found that it was massively over-oiled and I saw what looked like corrosion on the feed ramps. I did a full cleaning and it seemed to dry cycle fine after that, so off to the range I went.

I put 20 rounds in the mag, fired the first shot and the second round didn't feed, just like before. I tried it a few times and the problem existed with every attempt.

I pulled the mag out and dropped a single round in it and it fired fine. I figured it was too dry, so I oiled it like like the previous owner did and it fired a full 20 rounds with no problems. Went to start a new mag, right back to the BS feed and jam issues.

After getting some help from a couple of friends at the range and taking it to their shop to have an armorer take a look at it, it looks like the store I bought it from built the gun wrong, using incorrect parts.

[GeneFrenkle]

What did the company assembling it have to say? It'd be interesting to know who they are.

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[MarcSpaz]

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I bought the gun from All Shooters Tactical in Woodbridge.

Honestly, I did not take it back to them or even talk to them about. I figure if they are not competent enough to acquire and correctly install the correct parts the first time, I'm not going to trust them to do it a second time. It wasn't just one thing either. That is a lot of stuff to get wrong in one build.

That build wasn't all that went wrong with my experience at that store either. I brought a scope with a 1" body and the weapon into the store the next day and asked them to pick the right rings and install them. They sold me and installed a set of rings for $80. I wasn't to thrilled since it has a $60 hunting scope on it... but I figured why not. I planed on getting a much better 1" scope later and figured at least I had some decent rings. Well, the shop that is fixing the weapon for me now told me that I have the wrong rings on the rifle, as the recoil bar is too small for the rail system, so it's not going to hold zero.

Really? WTF? I can't catch a break with those guys. I am not going back there.

[GeneFrenkle]

Oh boy. Yea, I can understand. I've been living vicariously through this thread and after I read about the issues, I'm feeling heartbroken. Pls keep this thread updated, because I feel a need to see targets with ragged holes.

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[MarcSpaz]

Soon, I hope. I will bring my video camera and a still camera when I retest, just in case it actually works without having to replace the upper, the barrel extension or barrel.

I am just waiting for parts right now. Hopefully they will be in at the start of next week. The shop ordered all original DPMS parts to help ensure its right. I even bought 3 new original DPMS mags. No messing around this time. LOL

It would be nice to hit the 100 yard next Wednesday. Even if the scope moves on the rail, at 100 yards the grouping should still be good enough for what I want to do, which is say it works.

[MarcSpaz]

Well, I am still waiting on the buffer and buffer spring, but I did get a few other items I ordered. I figured I would share Hopefully the rest of the parts will be here by Saturday so I can get it tested.

The scope mounts are quick release. I figured it makes sense to have sights in case the scope gets broken in the field, keeping it usable even without glass. So, I picked up a nice set of Magpul Flip-up front and rear sights.

I also got a Magpul monopod and some 2 piece XTM enhanced rail panels.

[MarcSpaz]

For those of you who have been following my purchase and repair of the used DPMS .308, I have some good news for a change. My replacement buffer and spring arrived today.

I put the parts in and the weapon dry cycles live rounds with (almost) no issues. I literally pointed the weapon straight up to make the load as much as possible. It would manually eject the chambered round and feed the next round with only minor issues, but successfully.

The one issue I do have is on ejection. It takes putting the stock into my shoulder and pulling the charging handle using two hands to get the assembly to break loose. There is no way one or two fingers around the handle one handed will do the trick. Even with two hands, there is some significant effort required to break it loose. Once the bolt spins free from the locking assembly, all of the reset of the range of motion is perfect for what I would expect from and AR10 (based on AR15 experience). It is just starting that initial spin to get the bolt loose. I don't know if that is normal or not, but it seems a bit too much.

Any advice or comments there are welcome.

I am heading to the range Saturday for a live fire exercise. I'll video record the carnage. LOL Hopefully after several weeks I will finally have a functioning rifle.

[gunderwood]

It takes putting the stock into my shoulder and pulling the charging handle using two hands to get the assembly to break loose. There is no way one or two fingers around the handle one handed will do the trick. Even with two hands, there is some significant effort required to break it loose. Once the bolt spins free from the locking assembly, all of the reset of the range of motion is perfect for what I would expect from and AR10 (based on AR15 experience). It is just starting that initial spin to get the bolt loose. I don't know if that is normal or not, but it seems a bit too much.

Hard to say without seeing it, but the AR10 does take a noticeable increase in effort. I like putting BCM Gunfighters on mine; larger lever is my choice.

[MarcSpaz]

Well, I made it out to the range today. The gun fired awesome. No video I'm afraid. The owner said I could video record whatever I wanted as long as I erased it before I left. I wasn't sure if he was kidding of not... so I skipped it.

My armorer (Rob at VA Arms) let me know that the rings I had for my scope were not correct. He expected it to not hold zero, and he was right. I am not surprised since the same guys who screwed up the build also sold me the wrong rings. So, still need to spend a bit more money, but at least it finally works!!! LOL

Here is what the gun did at 100 yards, even with a scope that doesn't hold zero.

Actual size human silhouette.





Zoom of the bulls-eye.





A 6" in Dia. target.




This thing should be amazing with a good scope and mount.

[GeneFrenkle]

That looks great! Sounds like you're back in the saddle.! I'm really excited for you!

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[MarcSpaz]

Thank you Sir! I'm one happy camper.

[MarcSpaz]

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Admins / Moderators, if you feel this post is inappropriate, please feel free to remove it. This company does not appear to be a supporting vendor and I want to give people a heads-up.

For guys local to Northern Virginia, it is my opinion that you should avoid the gun shop "All Shooters Tactical" aka AST at all cost. They sold me a SASS conversion that was a hot mess, knew it (in my opinion) and didn't warn me about it.

Quick breakdown of what happened. The guys at AST sold me a DPMS LR-308. The lower is stamped. They said they bought the gun new and sold it to a friend of theirs. They said that they installed a new gas block, Troy free floating quad rail and a Magpul precision stock. They also told me that after two months, they guy moved and was selling the gun, so they bought it back. It's my guess and opinion that they screwed the build up, the owner got sick of it and bitched till they bought it back.

After working with DPMS and my local armorer, I found that the gun was a Frankenstein monster. The only mods done correctly were the gas block and the quad rail.

List of stuff wrong...
1.) Upper was not original for the lower (NBD... I guess. Looks like an upgrade)
2.) Barrel was not original for the upper (NBD... I guess. Looks like an upgrade)
3.) Feed ramps were scratched and had burs on the barrel side (had to file and polish)
4.) Chamber and leade were scratched (had to polish)
5.) Bolt and lower were heavily scratched (had to file burs and polish)
6.) Magazine catch/release was not installed correctly (corrected)
7.) Ejector spring was too big (replaced)
8.) The Magpul stock was for a carbine, not a full size rifle. (had to replace the buffer and buffer spring)
9.) Magazine was damaged from the bolt carrier striking it (replaced mag)
10.) Wrong scope rings (they charged me $80 for the wrong rings, still needs replacement)

[MarcSpaz]

Okay... I am having trouble selling my SASS... so like a chick I am waiting for the right moment to dump, I am keeping her happy so she doesn't get suspicious and make me miserable. LOL

I just bought a new Bushnell 6x18x50 scope. Before I get grief about not buying a Leupold Mark IV or some other high-end scope... I have had some folks make a nice, wide variety of glass available for me to look through. What I found was that except for color tint for filters... I literally see no difference clarity between a $70 scope and a $3,500 scope with comparable characteristics. I am assuming its because my vision sucks due to an injury many years ago... but in any case... a reasonably priced scope was fine fore me. LOL

Anyway... I am off to the range tomorrow. We'll see how it goes.

[MarcSpaz]

Well, for a cheap scope... the Bushnell worked like a charm! Finally, after 3 other optics, I got one that is holding zero!

Have to thank JDonovan and Gunderwood. I appreciate it guys! They both spent a lot of time explaining the differences between the different optics, quality of glass, etc. Bushnell uses some very nice multi-coated lenses from Bausch & Lom in the model I have. Yesterday we had low light with the overcast and very light rain at 5:30 PM. The targets were in a dark 40 yard deep cover building. Even with the poor light and viability, it had a nice crisp, bright picture. Once it was zeroed, at 100 yards I was able to put 60 rounds in a 2"x3" group. Just about carved out the center of the target.

Should be a good first scope for this riffle until I can save some cash for the higher-end tactical scope later... probably next year.

Anyway... thanks for following along.

[rss12]

Yeah really don't know what you talking about. All Shooters Tactical, is a great organization to deal with. If you had problems with a firearm, should it to get back. The guys at All Shooters Tactical would've helped you out in any way to get the problem straight. AST doesn't do machining, so whatever you bought was done somewhere else not by them. Whoever told you that burs on the bolt, and then charge you to file them off was way out of the bounds. That means of bolts never been used. Whoever you took that rifle for all that work put the screws to you. Obviously you don't know that much about guns, maybe you should read a little more before you buy again.

[MarcSpaz]

First of all, the guys at AST lied to me about the condition of the gun. I asked if anything was wrong with it. They said it worked fine, had less than 1000 round through it and their buddy needed to sell because he moved somewhere he couldn't take it.

Secondly, they told me they did all the work and the gun did not work. It's not a guess. It's their own words.

Third, I didn't pay 10 cents for labor. I got a second opinion from a reputable shop who also correctly installed the incorrectly installed parts for free. Most of the money spent was to replace the bent/damage magazine and the very obviously wrong buffer spring and buffer that were damn near 6 inches to short. I also needed to replace an extractor spring that was too big. I did all the labor myself.

Lastly, don't create an account to come in here and stir crap up when you have zero clue as to what you are talking about. They sold me a broken rifle that I had to fix. In my opinion they clearly lied to me and obviously have no clue how to mod a rifle, they have no business being in business if with some minor free advise I could fix a rifle they broke.

[darkstar3d]

Perhaps he is affiliated with AST. If so, say it. I new here but have been around boards a long time and this is one if the stinkiest first posts I've seen.


Retired Army Paratrooper