Range Rpt 300MP & 300 Gold Dots

[3rdgeargrndrr]

Sorry this wont be as scientific as Hoot's load workups,
but initial testing 450 Bushmaster loads with 300 MP powder With 300 gr XTP bullets were not inspiring.
Started getting pressure signs when things were getting interesting.

39, 40 and 41grain 300MP workups.
*Edit- 300 GRAIN HORNADY XTP MAG
POWDER: 300mp
PRIMERS CCI 450
OAL: 2.11, TAPER CRIMP JUST BELOW THE CANNELURE
Heavy STAB crimp to .475
Hoot bolt carrier lead slug modification, 20" barrel with Ross brake
temp 52 elev 118ft.
DIRTY TEST BARREL, 50 rounds fired previously from last cleaning VERY HEAVY SOOTING FROM THAT OUTING

Standard carbine buffer spring and buffer

Did not yet chronograph loads.

Groups 1.4-1.2",shrinking as the loads went up, unable to specifically measure first group as it shot very low right and spread between adjacent paper targets.




No sooting noted.

Case head Swipe beginning at 40grains, and unusable burred brass at 41 gr.

Primers looked normal at 40grain, flattened at 41gr. Stopped shooting due to pressure signs,
No blown primers.


Left to Right, 39, 40, 41 grain 300MP.



Thoughts,
CCI 450's are definitely a hot primer, I might need to back down to WSR or 400's. Ignition of powder shouldnt be a problem, all things kept same.
I seemed to have Dwell time issues in my rifle 300grainers need a lot of tuning to make them just right, considering to move the gas port forward.
Recoil quite stout IMO compared to 296 or 4227 with 300 grain projectiles. Cheek slap, shooting multiple group will induce flinch.
Stock AR trigger and carbine Lower setup not optimal for tight clusters
.

[Hoot]

By "side crimp" did you mean stab crimp? I suspect if that was the case, you were sending those bullets downrange anywhere from 2000 to 2200fps. IE, running hot as a function of strong bullet retention during ignition. If you ever get the urge to revisit 300MP and the 300 GD, repeat the exercise with a taper crimp down into the cannelure. However, If "side crimp" meant taper crimp, then I'm at a loss to explain what transpired with your recipe and you're right not to repeat it. With my experiments using the 300 GD/DC bullets, your accuracy results are consistent with what I achieved.

Hoot

BTW, it's -18.4F as I type this. I envy you being able to get out and comfortably shoot.

[3rdgeargrndrr]

Yes, heavy stab crimp, After cleaning the bore last night, there was a heavy amount of carbon buildup, took about an hour to finally get the patches clean. Makes me think of what It would be like to clean out a black powder rifle. I had lots of sooting from my previous load testing and in hindsight should have cleaned the bore out.

BTW I'm using 300gr Hornady XTP not the Speers. Just wanted to keep 300MP data in the same thread

I'm originally from Iowa, so I feel your pain but 52 deg here is downright cold to most Californians. Range was closed on Sunday due to Rain (and the Range liability issues).

[Hoot]

...snip...
BTW I'm using 300gr Hornady XTP not the Speers. Just wanted to keep 300MP data in the same thread

To be honest, if it were not for some members getting repeatable 100 yard MOA accuracy out of their work with the 300 grainers, I'd swear that our 1:24 twist barrels were too slow a twist for the velocities we can safely achieve, to get the same accuracy as we get from bullets in the vicinity of 250 grainers. A real head scratcher. Four different kinds of 300 gr bullets and I'm hard pressed to get them below 1.5 MOA and more often 2 MOA at 100 yards. Must be the way I hold my mouth.

Hoot

[3rdgeargrndrr]

I am only posting my results for my gun on this range day, YMMV

I shot the rest of my loads I had for the 300MP with HORNADY 300 grain xtp mags.
Admittedly, modified gun, different range and different day,
Changes to the AR-
modified action to to rifle length gas tube, hole ported to .125" with adjustable gas block(did not cycle with 0.093 gas port), Rifle length stock, changed to Colt bolt carrier (My factory carrier has the Hoot lead weight jb welded in), colt rifle buffer and spring.
Where I had pressure signs at 41 grains 300MP with the factory setup, I had none at 41.5g and 42.5g of the 300MP. Exact reasons for which I cannot say as there are many many variables different on this quick test day than my previous test.


Humidity 78%- light rain, temp 56 deg. elevation sea level
Did not bring chrony due to the light rain, didnt want to risk it.




Factory(fouling shots lol) 4 shot group of 0.54"

300MP - 300gXTP mag
41.5g 3 shot group of 1.27" - No fliers
42.5 g 3 shot group of 1.35" - No fliers -

Edit: 100yds. Prone off sandbags
2nd shot with 42.5g was a failure to extract/ very hard extraction, however case and primers showed no signs of overpressure.

I was able to get these two groups on one 7" target without a problem.I could have gotten all three on this target if I were to "shoot the square".

Notes: Recoil was significantly improved, than with the carbine length setup, even with all the weight removed from the bolt carrier and the heavy buffer. Off hand shots offer improved follow up due to reduced recoil. Muzzle brakes will make you NO FRIENDS at the range

A 1.35"MOA at 50-75yds may be overkill for hog hunting, but its cheap peace of mind. Will need to chrony this load sometime in the future to calculate muzzle energy and ballistics,
I know I know WC doesnt give a rats behind about energy numbers, but I would like to get this info up for the people who love numbers








I think the nickname Thumper should be replaced by Mjölnir



**EDIT 7/4/14:
I was finally able to Chrono the 42.5g 300MP/300xtp mag load, came out to 1950fps . Which is most likely overkill at 75yds. Comes out to 2533 ft lbs (15 ft from muzzle ), again, I'm using a rifle length gas system, cases are perfect now, no swiping noted, sooting is minimal at this load so far. Ran fine with Hoots Cheap carrier modification and the stock bolt carrier.
Recoil is now much improved, as the recoil impulse is decreased, and much more comfortable to shoot even for extended sessions.

I would like to attempt faster velocities and see how they group, as there is definite room for more velocity somewhere in here but for my purposes I am more than satisfied and this is the limit of my sanity. Also, blame the scarcity of the 300 xtp mag at the moment.
I dont ever plan on a 300-400 yard shot with this gun, which is out of my hunting ability.

Good luck,

[wildcatter]

I am only posting my results for my gun on this range day, YMMV

I shot the rest of my loads I had for the 300MP with HORNADY 300 grain xtp mags.
Admittedly, modified gun, different range and different day,
Changes to the AR-
modified action to to rifle length gas tube, hole ported to .125" with adjustable gas block(did not cycle with 0.093 gas port), Rifle length stock, changed to Colt bolt carrier (My factory carrier has the Hoot lead weight jb welded in), colt rifle buffer and spring.
Where I had pressure signs at 41 grains 300MP with the factory setup, I had none at 41.5g and 42.5g of the 300MP. Exact reasons for which I cannot say as there are many many variables different on this quick test day than my previous test.


Humidity 78%- light rain, temp 56 deg. elevation sea level
Did not bring chrony due to the light rain, didnt want to risk it.


Factory(fouling shots lol) 4 shot group of 0.54"

300MP - 300gXTP mag
41.5g 3 shot group of 1.27" - No fliers
42.5 g 3 shot group of 1.35" - No fliers

I was able to get these two groups on one 7" target without a problem.I could have gotten all three on this target if I were to "shoot the square".

Notes: Recoil was significantly improved, than with the carbine length setup, even with all the weight removed from the bolt carrier and the heavy buffer. Off hand shots offer improved follow up due to reduced recoil. Muzzle brakes will make you NO FRIENDS at the range

A 1.35"MOA at 50-75yds may be overkill for hog hunting, but its cheap peace of mind. Will need to chrony this load sometime in the future to calculate muzzle energy,
I know I know WC doesn't give a rats behind about energy numbers, but I would like to get this info up for the people who love numbers
I think the nickname Thumper should be replaced by Mjölnir

And this is a Major reason WHY Energy Numbers are for Marketeers and of little use for anyone else.

Consider: Hoot says your 300gr .452's are going 2000-2200fps and I concur. Pick a mean average, just for fun and it's 2100fps. The described loading has a FT/lb Energy of 2937ft/lb energy.

Compared to The 30-06, which can easily achieve 3000fps with 150gr bullets. which has a ft/lb energy number of 2997ft/lb Energy or 60 ft/lbs better the the 300gr 450b. So then, by conventional standards the -06 will out kill the 450b, RIGHT? In your minds eye you already know that this statement is Hugely False!!

Now, there are no numbers, produced from any formula, that will tell us in Real World circumstances which one is the better killer (with assured accuracy), but I and the ARMY's Wound Ballistics Center like the TKO model and when used in this example the -06 gets a TKO of 19.8 and the bushy load gets a TKO of 40.7!! So Now which one kills better and better suits what one Might actually see in the field??

..t

[Stealthshooter]

In your opinion is there more potential in the 300-mp for 275 grain and up bullets than there is with H110? Also is it any easier to ignite than H110? Getting ready to start working up a load for my barnes 285 grain spitfire-mz's. I think I have reached the peak performance with my 300 grain sst's and H110.

[Hoot]

In your opinion is there more potential in the 300-mp for 275 grain and up bullets than there is with H110? Also is it any easier to ignite than H110? Getting ready to start working up a load for my barnes 285 grain spitfire-mz's. I think I have reached the peak performance with my 300 grain sst's and H110.

Since I first began working with 300 MP, it has become apparent that it's performance is very close to W296. Either is an excellent choice for 275s and up. Lil Gun does work with the 275s, just at the edge of its sweet zone, but it definitely works. I haven't returned to work with it some more, but it's definitely in the future to retest with the Bartz upper.

I've been offline recently due to health issues, but have turned the corner after some R&R visiting my dad and intend to get back at it before comfortable shooting weather departs up here

Hoot

Edit: Almost forgot. It lights off fine with my primer of choice, Rem 7 1/2.
Edit again: I have never worked with H110, so I don't know how it behaves. Something else to add to my bucket list

[Stealthshooter]

Hey Hoot

H110 is the identical twin brother of w296. I can interchange them with zero difference.

[Hoot]

Hey Hoot

H110 is the identical twin brother of w296. I can interchange them with zero difference.

I can't say that for W296 and 300 MP because I never loaded them alongside one another, all else being equal. Add that to my list.

Hoot