load data for 7mm LRM

appreciate all the advise guys , i did notice when i released pressure with my right hand crosshairs moved left. i made an effort to pull straight back and not put so much cheek pressure. and i actually shot bullets at .020 off lands instead of touching. results much better group below is with 70 retumbo
 

Attachments

  • image.jpg
    image.jpg
    66.7 KB · Views: 165
Those look a lot better, especially the first pic with Retumbo. No vertical, the horizontal I would most likely say is still do to check pressure. Also you can try being behind the gun more, some people like to shoot more from the side. Which is fine for lesser recoiling rifles but something that pushes a bunch you need it to come straight back and not to the side.

As stated before, pull back then slowly release pressure. If the cross hairs do not go in a straight vertical line don't waist the shot. Look at your rear bag make sure it is straight and that the rifle is square in the pocket of your shoulder.

Like I stated before; this is not to Dog you on your shooting form especially with out seeing it, but this is the first thing that sticks out when looking at your groups.

I would try the 70gr of Retumbo again with less check pressure, and I would most likely add a 1/2 grain to the H-1000 and see what it does. That is as long as it is not showing pressure now, if so go down a 1/2 grain.


Sam
 
sorry took pic wih i phone in car groups are actually stringing vertically, target was with 12 in the up position,
 
Gotcha I guess I should have looked at that. If you are using a nice firm constant pressure and you are not showing pressure I would recommend going up on the charge in 1/2 gr steps. You should start to see what the gun wants. Most gun's will tune up on few nodes, on the hot side and low side, you just have to see where you are at.
 
thanks this is such a learning process. the thing that stinks is that i have 2 lbs of retumbo left and 3 rifles that love it, i have to have 4 that love it with 8 lbs of h-1000 staring me in the face. wonder when it will be in stock again
 
Tried some US 869 powder yesterday with 180 hybrids in the 7mm/375. 26" Rem 7 Rem mag takeoff rechambered to 7mm/375 (not the LRM)

Worked from 85 gr to 90 gr of powder.

87 gr 3050
88 gr 3090
89 gr 3125
90 gr 3150 signs of excessive pressure

88 and 89 showed accuracy potential. May need to do some tweaking.

So far most accurate loads with this rifle:

74 gr of H-1000 a lackluster 2935 fps--- shoots tiny cluster
77 gr of Retumbo 3030 fps -- shoots tiny cluster
88 gr of US 869 3090 approx. 1/2 MOA
89 gr of US 869 3125 approx. 1/2 MOA


I have a feeling the Retumbo will end up with the most usable load. Not sure the US 869 is going to tighten up.


I am showing this information for the 7 LRM users. It would appear that all three of these powders will work for this cartridge. Naturally the 7 LRM will have to start with lower charge weights.


As a side note I have made four 7mm/375s with various actions/magazine lengths and barrel lengths to learn what works and doesn't. No harm done as all barrels were takeoffs. Earlier I used 84 gr of RL-33 in two of these barrels BUT for some reason the accuracy just wasn't consistent.
Didn't tweak neck tension or seating depths. Jumps to rifling were approx. .150". Considering having the reamer throat shortened and buying a throating reamer so I can tune for magazine box restrictions.

The beauty of this size cartridge is that it cleans up 7 Rem mag chambers without setback. Not sure if the 7mm LRM will do this.
 
thanks this is such a learning process. the thing that stinks is that i have 2 lbs of retumbo left and 3 rifles that love it, i have to have 4 that love it with 8 lbs of h-1000 staring me in the face. wonder when it will be in stock again

I know how you feel I bought 8lbs of H1000 knowing I was going to build a LRM and now everybody is saying the same thing that it doesnt like the powder without pressure.

I NEED SOME RETUMBO
 
These days it is a real pain to find our favorite powders. H-1000 works and is very accurate. It just didn't get the 180 moving as fast as Gunwerks suggests. If it is all you can find use it.

Just crunched the wind drift at 4000 ft for my deer hunting area. Compared the velocities I got with the three powders: 2925 fps vs 3000 fps vs 3100 fps:
got 8.8, 8.3 and 8 inches drift at 500 yards respectively. Only 8/10ths of an inch difference! Sure drop may be more but that is why we use ballistic programs for our come-ups. Use what you have I guess.

After searching months for Retumbo, I got mad and called Hodgdon directly and asked where is the Retumbo? I was told names of two distributors to contact. Hodgdon said they might know of a store that had some.

First distributor named three stores in NC and Virginia. First one in NC would only sell me a pound at a time. Second store had four pounds and would sell them all to me. I took a hit buying them @ 40.50 per lb. Each pound sold for 27. 50 but adding Hazmat and shipping brought up the difference.

I have found that if the purchase is 8 lbs I can beat our local cost of $31 per pound after taxes. Recently got the 8 lb container of US 869 at Graf and Sons for $199 which breaks down to
$24.88 a pound!

Here are the two distributors:

800-992-6504 Parks and sons distributors:

Stores Parks and sons mentioned:

Duncan gunshop 336-667-6303 NC 1 lb at time
Dances sporting goods 804-526-8399 Virginia -------this is where I found 4lbs.
Ed and Dale 336-667-2830 Never called them


Other distributor I didn't call:

Sunset dist 641-847-2464 distributors:



I'd bet if you are persistent you can get some Retumbo. It worked for me.
 
I talked to a guy today who is having the same issues I am. He is shooting 2 and 3" groups at 100 and blowing primers and leaving ejector marks from excessive pressure. He is shooting gunwerks factory ammo. there's definitely a problem here I Just don't know if gunwerks realizes it. he also stated that his friend had the same pressure issues with his lrm. I have talked to the guys at gunwerks numerous times but they are not too enthusiastic about my concerns. It is disappointing but then again I don't know how many folks like me they talk to each day. Hard to believe there is a difference in my chamber and one in there rifles. And hard to believe their rifles have any pressure issues with their ammo
 
I talked to a guy today who is having the same issues I am. He is shooting 2 and 3" groups at 100 and blowing primers and leaving ejector marks from excessive pressure. He is shooting gunwerks factory ammo. there's definitely a problem here I Just don't know if gunwerks realizes it. he also stated that his friend had the same pressure issues with his lrm. I have talked to the guys at gunwerks numerous times but they are not too enthusiastic about my concerns. It is disappointing but then again I don't know how many folks like me they talk to each day. Hard to believe there is a difference in my chamber and one in there rifles. And hard to believe their rifles have any pressure issues with their ammo

WOW!!! Sounds like you got the same reaction I did when I asked them if they had any data yet on the 175gr NOS LRABs for the LRM. The answer I got was "no load data yet.", but I get 3 emails from them wanting to know if I still need 7LRM dies since Im borrowing a set now. Sounds like once they have your money they don't care after that.
 
Warning! This thread is more than 6 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.
Top