Pushing a 300 gr JHP with fastburning powders?

[WestbayWhisper]

Can it be done in the 1000 fps range with powders like Norma R1 or Vv N310?
Barrel 17.5". Want the minimum muzzle report with suppressor.

 

[Ditchtiger]

What are you shooting? Rifle? Handgun?

 

[WestbayWhisper]

Suppressed Ruger 77/44

 

[Ben Shepherd]

Maybe.....

IF you have access to a chronograph. But:

Work the load up VERY slowly(like .2 grains at a time).

 

[WestbayWhisper]

Yes Ben,
I have a chronograph. Where would you start? Found one post suggesting 7.2 gr Vv N310 was max load - but that was with 300 gr hard cast. Another shooter said that jacketed bullets need another grain compared to hard-cast ones.

 

[Ben Shepherd]

Assuming you can verify that charge as max in a respectable manual I would start at 6.4 then. From there go to 6.6, then 6.8 then 7.0 then 7.2, etc.

At each step you should see a similar velocity increase, i.e:

If 6.4=800 fps and 6.6=830 fps and 6.8=860 fps then 7.0 should be 890 fps. Stop when you hit your desired velocity, or when you start observing high pressure signs, i.e:

Blown primers
Pierced primers
hard extraction
Case head expansion
No velocity increase with an increase in powder charge
drop in velocity with increased powder charge.

It is time consuming, but I've had loads go from OK to tap the brass out with a rod and mallet with only a .5 grain difference.(In fact I was working with blue dot under a 300 hard cast in 44 mag)

SLOW and CAREFUL is the order of the day when you decide to "push" a load like you're wanting to.

 

[only1asterisk]

Load data previously posted was minimal, but safe in my gun. In some guns it evidently can be slow enough for a bullet to stick in the barrel. If anyone needs additional info please PM.

WestbayWhisper

The N310 load is maximum. Start at x grains. Work up slowly looking for the combination of velocity, accuracy and sound level you want. What bullet are you using?

You can get quieter loads by deep seating the bullets and using smaller powder charges.

David

 

[WestbayWhisper]

only1asterisk:
Im using Hornady XTP an seat them to the top cannelure (actually wrecked 2 cases today when learning to make the flare and proper seating - yes true newbie in handgun reloading)

Ben:
tnx a lot! I figured the starting load should be just above 6 grains. Im aware of hi-pressure signs since I fired an ogival barnes X in my 6.5 swede and had to open the bolt handle with a sledge hammer! Case and primer came out separately. The rifle rested on sandbags and me around a corner pulling the trigger with a string. It was pedagogical! An alternative to N310 is the somewhat more cool-burning N330 which I have exact data on.

 

[only1asterisk]

Load data previously posted was minimal, but safe in my gun. In some guns it evidently can be slow enough for a bullet to stick in the barrel. If anyone needs additional info please PM.

WestbayWhisper,

I don't have one of those bullets on hand. What is the over all length of a loaded round?

The reason I suggested starting at x grains of N310 is that is the lightest charge I'm fairly certain will not stick a bullet in your barrel (taking into consideration the variations in bullets and not knowing the exact OAL).

David

 

[WestbayWhisper]

COL is 1.61 inches. Started with 3 rounds 6.0 grains N310 through my Chrony today 627/643/692 fps. Ouch - no SEE or hi-pressure signs but a long way to go up to the 1000 fps with a fastburner. Think I should save the N310 for my .223 subs and let the mrs buy some N330 when she visits Stockholm this week. Somebody on this forum has already done this job...its stupid not to listen

 

[only1asterisk]

That's about 75fps slower than my 16" barrel with the Nosler bullet with the same load. Don't reduce under 6 grains! In fact, the 6 grain load could still stick a bullet in your barrel. I'll add a note to that effect to my post above.

Was it quiet?

What bulky shotgun powders are available to you?

David

 

[WestbayWhisper]

Only1asterisk:
No, I wont reduce it any more and dont think I will increase it over the 7.0 grains I tested today neither. From 6.6 grains and up didnt gain any speed but big differences in velocity - like Ben Shepherd told me could happen! Bulky shotgun propellants - dont know any brand. The load was quiet but to be true I dont have the suppressor yet, actually send the rifle to the suppressor technician today and in about two months it will be returned I hope. Just wanted to test the powder in advance - and the stability of the 300 gr in 1:20". 3 big perfect circular holes at 110 yards!

 

[Ben Shepherd]

You got wild velocity swings but no linear increase vs. powder charge right?

If that's correct, you could try your loads again using dacron wads as filler to try and eliminate powder position issues.

Agian, it's time consuming, but it may work.

EDIT:

Not sure how that filler will react in the suppresor.

 

[WestbayWhisper]

Yes, from 6.0 to 6.6 gr it looked linear and with uniform velocities but from there erratic. I thought the use of filler would be less the more powder I put in the case? Ill post again when the (suppressed) rifle is back. Then also report som experience with N330. Thanks again!

 

[Ben Shepherd]

Just not sure how filler will react in the suppresor. It may plug things up?

Good luck!!! And make sure you post an update.