300 HAMR and a Primer?

[STIHL]

Yes, this is a 2 part post with the first telling you the rifle specs and then asking what is working well for you all.

Rifle is a Anderson upper and lower with various parts to finish the lower it will sport a mag oil PRS stock, I bought off my buddy, and a rifle length buffer tube and buffer. Went with a LANTAC BCG, The pictures looked better on the internet, but it is a nice carrier. Wilson 18” 1:13 twist fluted barrel and it will be wrapped in a aero precision s-one hand guard. Will be shot suppressed more than likely. Can is a silencerco hybrid.

Now to the question, looking through load data getting my research in I’m seeing small rifle mag primers specified, I know there is no way to know until you try but before I prime 100 cases o want to hear the real world results. I have no small rifle mags. What I do have is some rem 7-1/2, CCI, and Winchester and I have a box of the fed GMM. What is the hottest burning primer of those. I have 0 data with small primers to tell a difference. The powder I have chosen is CFE BLK which, please enlighten me, is going to be a ball powder? That I am assuming is going to be hard to get good ignition and that’s why mag primers were used.

2nd question is what’s the accuracy your seeing and with what bullet. I’m liking the 125-130 range for This rifle. Speer hot cor, Sierra game changers, SST, etc I haven’t gotten any bullets ordered yet, I have plenty of 150s to try out, but I feel it’s not enough horse power for a 150 grain bullet.

Appreciate any information.

 

[Hawk]

I'm loading the 7.62x40 Wilson Tactical, which is the predecessor of the 300 HAMR.
I use Rem 7-1/2 exclusively and AA1680 with the 125 Sierra Pro Hunters and get excellent accuracy.
Do you plan on buying factory brass or making your own from 5.56/223?

 

[popper]

I just load BO but Hornady specs mag primers for all loads. I tried them. CCI srp worked fine. Mags cleaned up 2400 powder burn a bit, all I could see. 135 FTX and 23 gr CFEB is near max and gives 2K fps for the hamr. I recently tried the 160 ftx in my BO - slower but good expansion, accuracy and penetration.

 

[STIHL]

I'm loading the 7.62x40 Wilson Tactical, which is the predecessor of the 300 HAMR.
I use Rem 7-1/2 exclusively and AA1680 with the 125 Sierra Pro Hunters and get excellent accuracy.
Do you plan on buying factory brass or making your own from 5.56/223?

Bought 500 new factory Starline. Too cheap not too. .29 cents a piece. Caught them on sale when o bought my barrel and got free shipping on them so it was a win win for me.

 

[STIHL]

@popper i havent had issue with the standard smalls in 300 blackout stuffed full of H110 either, never paid attention to the loadings calling for mags. I should be alright with any primer, but seeing as I have a few rem 7.5 that need to be used up I’m going to shoot them and see. Going to start with 100 cases and if it doesn’t work I won’t have as many to deprime, or just try out with a different powder, never hurts to see if something else works.

 

[CWLONGSHOT]

Cannot comment to actual experience with the HAM'r. Altho I gave it a hard look and only passed cause its not conducive to cast. But I also dont feel all guns must shoot my cast.

I have done allot of 300 bo shooting and taken 20+ deer and a few coyotes with the lil 300 from Single shots, Bolts and multiple M$R rifles. Using a number of different bullets and I have my favorites. I have a couple hunting buddies who also use the 300 and same loads.

In the hammer The excellent Speer 130fp would be awesome as the lil 300 is real good inside 50/60 and past 100 it dosent expand well at all. So the velocity threashold is a bit high for the BO unless your real close.
The Hornady 125 SST is been used the most as its my buddies favorite and it ALL HE WILL USE. NEVER lost a critter, NEVER had poor penetration. Meaning all are thru and theu. Every single one died in sight or DRT.

THE Sierra 125 HP FP is junk. It comes apart and gives shallow penetration. Almost lost both deer I shot using the bullet. Muzzle velocity was 2250fps.

Sierra 125 Sp is a good choice more dureable then the 125sst but not as tough as the 130 Speer.

The 125 NBT is a good choice and should be good in HAM'r.

The 135 FTX is my top to choices. Suprizingly, its more durable then the 125 sst! I load mine in my bolt only cause the load is hot for the M$R's. 300MP powder. Slightly above book @ 20g. Muzzle vel is 2150 fps (Work up to) Only one deer so far. Thru and thru with nickle exit and pulped lungs.

Second & tie for first, for me is the Speer 150g Gold Dot. The one made for the 300bo. Loaded with IMR4227 @ 1925 fps. This one has three maybe four deer and all so far have been DRT.

The FTX 160 was tested in 30/30 but loaded to 300 speeds and that bugger expanded down to 1100 fps!!!! I load mine with 1680. (You cannot get too much of this powder in the lil 300 case) 1900 is about most I can get as 1680 simply dosent compress. But this could be a awesome 300 bullet!

The last one I really like is the Sierra flat base 135g HP Varmint bullet. Now know this can be fragile at top velocities ir on heavy bones. But lung shots at any sane 300 bo range this bullet is a bomb and accurate!


I machined off 1/2 of many appropriate bullets to see how they was made. (Looking for my pics)

 

[STIHL]

CW, I had looked at the mono flex hornady bullet as a real contender too. It’s not out for he question either. I’ve been very impressed with the bullet in my 45-70. That’s a lot of good information, settles my sights on the 130 hot cors for now. If o can get my hands on some others I may try them as I can get a hold of some here and there.

 

[CWLONGSHOT]

I haven been able to get these to test. But should be good I agree.

 

[sundog]

My experience with both the 300 Ham'r (15 twist) and 7.62x40WT (12 twist) is that they can shoot cast very well. Each was set up in an AR-15 with Wilson barrels. Two bullets tested were the RCBS 7.62-130-SPL and NOE 311-152-SP, both GCd and PCd. BTW, both of those shot jacketed exceedingly well. Like any other, just have to find what it likes.

Those two bullets also shot well in 300 BO (8 twist) and 7.63x39 (10 twist), both AR-15.

So, yes, it can be done if you want to spend the time fiddling around with it.

 

[CWLONGSHOT]

My experience with both the 300 Ham'r (15 twist) and 7.62x40WT (12 twist) is that they can shoot cast very well. Each was set up in an AR-15 with Wilson barrels. Two bullets tested were the RCBS 7.62-130-SPL and NOE 311-152-SP, both GCd and PCd. BTW, both of those shot jacketed exceedingly well. Like any other, just have to find what it likes.

Those two bullets also shot well in 300 BO (8 twist) and 7.63x39 (10 twist), both AR-15.

So, yes, it can be done if you want to spend the time fiddling around with it.

Thats good news!

I spoke directly with Bill Wilson thru emails and after a couple back and forth he said because of the very tight chambers required for these higher pressures. Cast would be difficult at best PC with its increased dims would make that an effort in futility. (I believe was his words)

I like everything else about this caliber. Its not really a negative as the BO really hasnt been stellar with cast same for my 223 M$R and my 6.5 Grendel. My Mossberg bolt 223 is OK with cast. My point is I have others I dont shoot cast n so another shouldn't be a negative.

CW

 

[STIHL]

Unfortunately this isn’t a cast rifle project for me yet, it’s going to eat jacketed. I’ve got a project for one of my 30 cal rifles after season is over going to do some accuracy improvements to both of them and see what they will do with a jacketed load then a cast, and take the best one for a cast rifle.

I’m more concerned over lighting off that case full of CFE BLK with a standard primer vs a mag. That’s been my main concern. According to Bill Wilson this this will shoot 110-150 grain projectiles very well. Near 30-30 performance, doenst make it a 30-30, but with the right bullet, which I believe is a 125-130 grain it’s going to be a dandy little rifle that will do very well on targets and a white tail if I ever choose to use it for hunting. I have enough hunting rifles, but I have shot my. CVA Scout 45-70 exclusively the last 2 years.