Page 1 of 4 1234 LastLast
Results 1 to 10 of 32
  1. #1
    Platinum Member westcliffe01's Avatar
    Join Date
    May 2009
    Posts
    990
    Location
    SE MI
    Tractor
    Bobcat B200 TLB

    Default Range report - DPMS 7.62x39 carbine

    A couple of weeks ago I took my DPMS carbine chambered in 7.62x39 to the range for the first time and was very disappointed. The only manufacturer who makes magazines for the rifle had gone out of business (C-Products) and now I think I know why.... The rifle absolutely would not feed ammunition from the 30 round magazines. Not when loaded with 30 rounds, nor 20 nor 10 or even 5 rounds......

    So I had a very frustrating afternoon and ended up feeding rounds manually into the breach to sight in the scope that I had fitted, a 1-4x20 Nikon Monarch. I went home, disassembled the magazines to see what was in them and figure out where the problems were. Needless to say, the magazine feed lips, follower, spring orientation all needed work. I also stripped the upper receiver and was amazed by the amount of brass everywhere so set to work getting things to work smoothly there too.

    One of the things I discovered is that in order to get a good color match on parkerizing or plain blackening, the manufacturer will typically do some kind of media blast to get all the surfaces to the same finish, that way, there are not different shades in the color when blackened/parked. The problem is that the blasted surface is not very smooth and this has a significant effect on operation. I ended up using fine emery paper and smoothing the finish on the lower surface of the bolt carrier that rides over the hammer and the top round in the mag when on its rearward travel. The guide rails on the bolt carrier were smoothed too, since these are the primary guide surfaces and they are only running in hard anodized aluminum, so rough finish and sharp edges will make for rapid wear.

    Starting out, I could not get 2 rounds in succession to feed in the "as purchased" condition. I was able to improve this to the point that I had only 1 misfeed out of 4 magazine loads (120 rounds). I now do not load more than 20 rounds in the magazine, since the design makes a full mag less reliable. I also ordered 2 5 round magazines and had to rework them, but at least the geometry of the feed lips and the top of the mag was fine. The problem was with the follower and operating spring.

    This weekend I was able to fit in another range trip and test the new 5 round mags and just generally see how things were working out. I was shooting Yugoslavian surplus, which has been for sale at $184/1120 round case, but just recently there was a 50% increase in the cost of this ammo.

    At 100yds, other than 1 flier, I was able to keep 9 rounds inside the 3" circle on the target. The Nikon scope is relatively low power and at 100yds the aiming point is all but obscured by the cross hairs of the scope.
    Attached Thumbnails Attached Thumbnails -dpms-1-jpg   -mags-yugo-jpg   -100yd-dpms-jpg  

  2. #2
    Platinum Member westcliffe01's Avatar
    Join Date
    May 2009
    Posts
    990
    Location
    SE MI
    Tractor
    Bobcat B200 TLB

    Default Re: Range report - DPMS 7.62x39 carbine

    One of the limiting factors besides the low magnification optic has been the trigger pull. I had never done any work on triggers before and have looked at aftermarket triggers, but $200+ seems like a lot of dough for a trigger.... The trigger on this rifle has a long gritty take up and breaks at a high force. After more web surfing and wincing at the prices (I only paid $850 for the whole gun, after all) I decided at the very least to look at the offending parts to see what was going on.

    With the lower disassembled and the components on the table top, it was really obvious that several things were going on. 1) The sear surfaces had clearly visible and "feelable" burrs from machining. 2) The machining process left directional machining marks and these were 90 degrees to the direction of movement, so that was the obvious reason for the "gritty" feeling during release.

    Not being an expert and having no mentor (yet), I decided that I would try to improve the surface finish on the working surfaces, without changing the depth of engagement, operating angles or spring preload. The surfaces on the trigger itself are readily accessible in this design, but the surface on the hammer sear less so. I dug out the finest wetstone I had and lapped all the surfaces on the trigger until I removed all machining marks. I was able to use a lapping direction aligned with the direction of motion on the trigger. On the hammer, due to the relatively narrow width of the sear, the only option was to lap across the sear (90 deg to movement) but I was able to substantially improve the finish and remove all the burrs.



    When re-assembled, the length of take up is the same as before, but now it is really smooth. It seems as if the break is at a slightly lower force, but that may just be due to the removal of the burrs. Anyway, for an hours work, the trigger feels vastly better than before, even though I made no significant changes other than surface finish on the parts. I didn't touch the safety sear which locks the hammer until the trigger is released for the next shot, and verified that the safety slector still functioned as intended. So I will be off to the range again today to see if I can tell any change downrange. As it is, the accuracy is fine for hunting out to 150yds. I chose the caliber since it is legal for deer hunting in MI, as well as availability of surplus ammo.

  3. #3
    Super Star Member k0ua's Avatar
    Join Date
    Jun 2009
    Posts
    14,936
    Location
    Branson, Mo.
    Tractor
    Kioti DK35se Hydrostat

    Default Re: Range report - DPMS 7.62x39 carbine

    You sound like the kind of guy that could benefit by having some of the proper tools, You are doing good with what you have, but you could do better with the proper tools. Go to Brownells and get everthing you need in the way of tools and parts

    Brownells Search : Search Results for "stone" - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools - BROWNELLS

    James K0UA
    James KUA

    Kioti DK35se hydrostat with 2 QA buckets, 48 inch. King Kutter Rotary Cutter. 750 lbs ballast box. Loaded tires, Construction Attachments SSQA Lightweight Pallet forks. EA 50 inch single lid "wicked" Grapple. Satisfied Everlast PA160 welder owner How to add a link to a post . Best way to search TBN


  4. #4
    Elite Member Kyle_in_Tex's Avatar
    Join Date
    Oct 2002
    Posts
    4,350
    Location
    Giddings, Texas
    Tractor
    JD 4310,JD5420

    Default Re: Range report - DPMS 7.62x39 carbine

    Thanks for posting. Good info. At some point, you'll be up against the limitations of the ammo and the barrel.
    there are 2 kinds of oats. Oats in front of a horse, and oats behind the horse.

  5. #5
    Elite Member jonyyuma's Avatar
    Join Date
    Sep 2010
    Posts
    2,972
    Location
    35 miles North of Memphis,TN
    Tractor
    kubota L3000dt, ford 8n1952

    Default Re: Range report - DPMS 7.62x39 carbine

    You will be surprised what that caliber will do with some good ammunition. Be aware that that ammo is loaded with more than one diameter bullet....I have several of these rifles by diff. mfrs.20 inch barrels or longer stabilize the bullets best.
    Okay, Legal disclaimer: Old but not senile, definitely do not have the answer to everything!

  6. #6
    Platinum Member westcliffe01's Avatar
    Join Date
    May 2009
    Posts
    990
    Location
    SE MI
    Tractor
    Bobcat B200 TLB

    Default Re: Range report - DPMS 7.62x39 carbine

    Someone may be able to enlighten me as to the feasibility of reworking the berdan primed cases to accept boxer primers ? I could make a form tool to ream out the primer hole and drill a new (central) flash hole. A Mini lathe will be more than adequate for the task. I will eventually have nearly 2500 of these berdan primed brass cases and new brass is more than 50c each !

    I have started looking at hand loading and one is looking at 30c for a bullet, 4c for a primer and 4c for powder, so 38c for those parts that absolutely have to be replaced. If one gets 10 reloads out of the brass one is looking at an all up cost of $44/100 rounds which is a lot better that commercial ammo.

    James, thanks for the link to the source for hones. Lots of new stuff for me to consider.

  7. #7
    Platinum Member westcliffe01's Avatar
    Join Date
    May 2009
    Posts
    990
    Location
    SE MI
    Tractor
    Bobcat B200 TLB

    Default Re: Range report - DPMS 7.62x39 carbine

    I speak under correction... Apparently one can purchase NEW wolf magnum Berdan rifle primers for $17.50/1000. Wideners has them in stock. Looks like I need to get 10k of them on order pronto !!!

    http://www.wideners.com/itemdetail.cfm?item_id=8481&dir=278|284|737

  8. #8
    Super Star Member k0ua's Avatar
    Join Date
    Jun 2009
    Posts
    14,936
    Location
    Branson, Mo.
    Tractor
    Kioti DK35se Hydrostat

    Default Re: Range report - DPMS 7.62x39 carbine

    Quote Originally Posted by westcliffe01 View Post
    I speak under correction... Apparently one can purchase NEW wolf magnum Berdan rifle primers for $17.50/1000. Wideners has them in stock. Looks like I need to get 10k of them on order pronto !!!

    http://www.wideners.com/itemdetail.cfm?item_id=8481&dir=278|284|737
    There are 2 or 3 methods to punch out Berdan primers, and from what I have heard they all suck. I have never done it. There is a method of going in from the outside at an angle and flip them out. there is a the hydraulic method, of filling the case with water and putting in a plug and hitting it with a hammer, and then there is a double prong punch that fits the 2 little flash holes. Please take into consideration how you are going to decap the brass before you invest a bundle. I would order 100 first and get the process down pat before I spent the farm.What kind of press do you have?

    James K0UA
    James KUA

    Kioti DK35se hydrostat with 2 QA buckets, 48 inch. King Kutter Rotary Cutter. 750 lbs ballast box. Loaded tires, Construction Attachments SSQA Lightweight Pallet forks. EA 50 inch single lid "wicked" Grapple. Satisfied Everlast PA160 welder owner How to add a link to a post . Best way to search TBN


  9. #9
    Platinum Member westcliffe01's Avatar
    Join Date
    May 2009
    Posts
    990
    Location
    SE MI
    Tractor
    Bobcat B200 TLB

    Default Re: Range report - DPMS 7.62x39 carbine

    I found this at the following site dedicated to surplus rifles:
    Berdan to Boxer Conversion Method in Handloading Forum




  10. #10
    Gold Member
    Join Date
    Jan 2011
    Posts
    408
    Location
    PA
    Tractor
    L35,1910,580D,933C,935B,MS90,N-11,Z60,310D,443,553,885

    Default Re: Range report - DPMS 7.62x39 carbine

    Bushmaster XM-15 sounds like a bargain after the ordeal described...
    What could possibly go wrong? *#^@*! I think it is time for a drive.

Page 1 of 4 1234 LastLast

Similar Threads

  1. Using loader in low range sure makes difference
    By cdcole in forum New Holland Owning/Operating
    Replies: 1
    Last Post: 07-26-2003, 04:52 PM
  2. Rural Living Adaptation of a City Dweller
    By DocHeb in forum Rural Living
    Replies: 56
    Last Post: 11-25-2002, 08:45 AM
  3. 3 Range Hydro for Class III Boomer?
    By TCowner in forum New Holland Owning/Operating
    Replies: 3
    Last Post: 11-11-2002, 06:41 AM
  4. Goodbye Kubota, hello EarthForce
    By MChalkley in forum All Other Brands
    Replies: 510
    Last Post: 04-22-2002, 04:07 PM
  5. Three Point Control Range UPDATE
    By RAllen in forum Kubota Owning/Operating
    Replies: 9
    Last Post: 05-23-2001, 11:08 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.