[InTheBlack]

Can't find any g**gle info searching for the Crane SPR variant.

From what I've read about 77 gr match ammo, its kinda tweaky and it doesn't shoot well for every rifle. At least requires lots of load development (Zediger).

I presume that Crane is doing something to optimize the leade & twist?

[444]

I am sure this subject has been covered on AR15.com.
If it hasn't, they are good guys to ask a qustion like this.
They have discussed the Crane SPRs extensively.

[MLC]

There was a SPR upper for sale here a few months ago.

[444]

A good source for a psudo SPR that is supposed to be very close to the real thing is www.mstn.biz

[762x51]

I contacted MSTN a month or so ago about having an SPR upper built and the price they quoted me was insane....something like $2700 if I recall. Check out Lane St John (his screen name is ArmyInf on ar15.com) for a more affordable option....he will be doing mine when I'm ready.

[InTheBlack]

Did a search for "SPR" on mstn and came up empty.

C'mon guys - if you're thinking about buying one you must know what it is you're buying!

[762x51]

Do a search for "SPR" on ar15.com and you will find a wealth of info.

[Jeff White]

From what I've read about 77 gr match ammo, its kinda tweaky and it doesn't shoot well for every rifle. At least requires lots of load development (Zediger).

All you need is a 1/7 twist barrel for the load Crane is buying from Black Hills. MK262 mod 1 is a 77 gr OTM bullet with a cannelure. For awhile Crane was buying up all of this ammo that Black Hills could produce. Georgia Precision has a quantity of it now. Don't know if they have sold out.

No problems with accuracy or terminal performance out of a 1/7 twist barrel. Accuracy has been spotty out of 1/9s. If you have a Bushmaster or other AR with a 1/9 twist test it before depending on it. If you have a 1/7 twist barrel just shoot it.

Jeff

[InTheBlack]

ar15.com doesn't have a search feature...

Anyway, a 1:7 barrel doesn't make a super-rifle. Most match rifles are 1:8 or a fraction faster; anyone with a 1:9 barrel has a very old upper.

Anyone have the ballistics of the Mod 1 cartridge? My browser doesn't work with the Black Hills site..

[444]

AR15.com does have a search feature. If you search AR15.com you can see a number of SPRs done by MSTN.

MSTN doesn't currently have any SPR uppers listed on their website, but send them an E-Mail or call them on the phone. They are one of the best companies I have ever dealt with; bar none. I have no doubt that buying one of their SPR uppers would be expensive, but it will be the best and as close to the real thing as you can get. I am very much "into" the AR15 platform and don't buy anywhere else. I don't ask price. I don't research anything. I call up MSTN and tell them what I want, or what I want to do and tell them to send me what I need. I don't ask any questions and three days later a package arrives with the best of the best.

1:9 twist barrels are pretty much the standard for you average AR15.

[gun-fucious]

http://www.thehighroad.org/attachment.php?s=&postid=176027

[InTheBlack]

Cool pics. They need to learn how to spell "tactical," though.

The Search on ar15 only works if you are a paid member :( but I found a thread by MSTN showing some they built.

I still don't know what makes this design a "breakthru" as compared to any other hand-built match grade rifle.

Does the "SPR contour barrel" have a harmonic sweet spot? Why 18" ? The brake is said to add accuracy, but that's probably again a harmonics issue, and could be duplicated by leaving more mass on the end of the barrel or with a weight.

What's the "M4 feed ramp cut?"

[444]

The search funtion works on AR15.com even if you arn't a registered member, but you are only allowed to search once per minute as a non member.

You can see pictures of M4 feedramps on AR15.com also. Trust me, just click the search button; it will work for you.

I don't think the SPR has anything over a target rifle for accuracy. But it is built tougher, and has the rails to mount military stuff on it.

[InTheBlack]

I see two blank white rectangles to the left of the Log In button on ar15.com. But no search button is visible. Might be my old browser.

Don't understand why an 18" barrel was chosen. 24" is usual for long range, and overall would still be handier than an M14. Unless the sound suppressor design drove it. But that's a whole 'nuther bewilderment. Don't see the usefulness of a sound suppressor when the target is more than 500 away. Which is the Designated Marksman's mission profile, right?o

[Jeff White]

Anyway, a 1:7 barrel doesn't make a super-rifle. Most match rifles are 1:8 or a fraction faster; anyone with a 1:9 barrel has a very old upper.

I never suggested it did. I simply stated that it seems to work best in 1/7. People I know who have fired it in 1/9 twist barrels have had inconsistant results.

The SPR was built to allow precision engagement of individual targets beyond 600 yards. MK 262 mod 1 provides adequate accuracy and terminal ballistics at that range. Ammunition was also procured that was loaded with the Hornady 75 gr match BTHP.


I still don't know what makes this design a "breakthru" as compared to any other hand-built match grade rifle.

It's not a breakthru match rifle. It is a purpose built military rifle designed to give a special forces operator a precision fire capability in a lighter package then any of the 7.62x51 weapons in the inventory and is also capable of performing some of the other missions that may be required ot the operator. Kinda hard to do CQB with an M24 SWS, but in a pinch you could do CQB with an SPR. I doubt you'll see SPRs at Camp Perry.

Jeff

[sanchezero]

http://ar15.com/forums/topic.html?b=3&f=12&t=167508

Thread on MSTN's SPRs.

For AR15.com search button, pick a 'community' from their homepage. You'll find the search button at the far right of the page a coupla inches from the top in black letters.

:cool:

[Jeff White]

Don't understand why an 18" barrel was chosen. 24" is usual for long range, and overall would still be handier than an M14.

Remember they wanted this rifle to be a handy little package. You can get acceptable accuracy out of 20" barrels at long range. Seems to me the 20" AR does ok for itself at Camp Perry.

Unless the sound suppressor design drove it. But that's a whole 'nuther bewilderment. Don't see the usefulness of a sound suppressor when the target is more than 500 away. Which is the Designated Marksman's mission profile, right?o

Remember the SPR is a multi role weapon. When you're carrying everything on your back, it's hard to use the arms room concept for different missions. The weapon needs to be able to do the sane thing as the M4A1s on the team.

This is the Squad Designated Marksman's mission statement:

IAW FM 3-22.9 (23-9) Rifle Marksmanship 31 JAN 03, Chapter 7, Section VII, pg. 7-48, para. 7-29:

"7-29. MISSION OF THE SQUAD DESIGNATED MARKSMAN

The primary mission of the SDM is to deploy as a member of the rifle squad. The SDM is a vital member of his individual squad and not a squad sniper. He fires and maneuvers with his squad and performs all the duties of the standard rifleman. The SDM has neither the equipment nor training to operate individually or in a small team to engage targets at extended ranges with precision fires.

The secondary mission of the SDM is to engage key targets from 300 to 500 meters with effective, well-aimed fires using the standard weapon system and standard ammunition. He may or may not be equipped with an optic. The SDM must, therefore, possess a thorough understanding and mastery of the fundamentals of rifle marksmanship as well as ballistics, elevation and windage hold-off, sight manipulation, and range estimation."

This is in the manual, but the Army currently does not have a formal SDM program. I know the Stryker Brigade out at Ft. Lewis is doing some work in that area, but what's posted above is the Army formal doctrine for right now.

The USMC on the other hand has two different programs. There are others here who are more qualified to comment on their programs then I am. As you can see, 300-500 meters is the SDMs operating range. In practice his range will be not much more then the squad's (0-300 meters) but he will have the capability to place precise fires into firing ports in bunkers, vision blocks in armored vehicles, windows and mouseholes in Urban Operations (forrmerly called MOUT). If equipped with an optic he will also be invaluable in locating targets for the rest of the squad.

Jeff

[444]

Ok, I figured out the confusion with the AR15.com search function. You have to register and log in to get it. I clicked on the link posted above and didn't get the search function. But when I logged in, it gave it to me. Note that I am not a paying member of AR15.com, but if you register, you are allowed to use the board. If you pay, you get more features.
My bad, I never tried it without being logged in.
Also, if you are a non-paying member, you can only search once per minute and you can only search posts from the last 30 days.
Sorry for the confusion.